Preface
Foreword
My journey to learn and better understand Linux began over a decade ago, back in 1998. I had just installed my first Linux distribution and had quickly become intrigued with the whole concept and philosophy behind Linux. There are always many ways to accomplish a single task. The same can be said about Linux distributions. A great many have existed over the years. Some still exist, some have morphed into something else, yet others have been relegated to our memories. They all do things differently to suit the needs of their target audience. Because so many different ways to accomplish the same end goal exist, I began to realize I no longer had to be limited by any one implementation. Prior to discovering Linux, we simply put up with issues in other Operating Systems as you had no choice. It was what it was, whether you liked it or not. With Linux, the concept of choice began to emerge. If you didn't like something, you were free, even encouraged, to change it. I tried a number of distributions and could not decide on any one. They were great systems in their own right. It wasn't a matter of right and wrong anymore. It had become a matter of personal taste. With all that choice available, it became apparent that there would not be a single system that would be perfect for me. So I set out to create my own Linux system that would fully conform to my personal preferences. To truly make it my own system, I resolved to compile everything from source code instead of using pre-compiled binary packages. This “perfect” Linux system would have the strengths of various systems without their perceived weaknesses. At first, the idea was rather daunting. I remained committed to the idea that such a system could be built. After sorting through issues such as circular dependencies and compile-time errors, I finally built a custom-built Linux system. It was fully operational and perfectly usable like any of the other Linux systems out there at the time. But it was my own creation. It was very satisfying to have put together such a system myself. The only thing better would have been to create each piece of software myself. This was the next best thing. As I shared my goals and experiences with other members of the Linux community, it became apparent that there was a sustained interest in these ideas. It quickly became plain that such custom-built Linux systems serve not only to meet user specific requirements, but also serve as an ideal learning opportunity for programmers and system administrators to enhance their (existing) Linux skills. Out of this broadened interest, the Linux From Scratch Project was born. This Linux From Scratch book is the central core around that project. It provides the background and instructions necessary for you to design and build your own system. While this book provides a template that will result in a correctly working system, you are free to alter the instructions to suit yourself, which is, in part, an important part of this project. You remain in control; we just lend a helping hand to get you started on your own journey. I sincerely hope you will have a great time working on your own Linux From Scratch system and enjoy the numerous benefits of having a system that is truly your own. -Gerard Beekmans gerard@linuxfromscratch.org

Audience
There are many reasons why you would want to read this book. One of the questions many people raise is, “why go through all the hassle of manually building a Linux system from scratch when you can just download and install an existing one?” viii

Linux From Scratch - Version 6.7 One important reason for this project's existence is to help you learn how a Linux system works from the inside out. Building an LFS system helps demonstrate what makes Linux tick, and how things work together and depend on each other. One of the best things that this learning experience can provide is the ability to customize a Linux system to suit your own unique needs. Another key benefit of LFS is that it allows you to have more control over the system without relying on someone else's Linux implementation. With LFS, you are in the driver's seat and dictate every aspect of the system. LFS allows you to create very compact Linux systems. When installing regular distributions, you are often forced to install a great many programs which are probably never used or understood. These programs waste resources. You may argue that with today's hard drive and CPUs, such resources are no longer a consideration. Sometimes, however, you are still constrained by size considerations if nothing else. Think about bootable CDs, USB sticks, and embedded systems. Those are areas where LFS can be beneficial. Another advantage of a custom built Linux system is security. By compiling the entire system from source code, you are empowered to audit everything and apply all the security patches desired. It is no longer necessary to wait for somebody else to compile binary packages that fix a security hole. Unless you examine the patch and implement it yourself, you have no guarantee that the new binary package was built correctly and adequately fixes the problem. The goal of Linux From Scratch is to build a complete and usable foundation-level system. If you do not wish to build your own Linux system from scratch, you may not entirely benefit from the information in this book. There are too many other good reasons to build your own LFS system to list them all here. In the end, education is by far the most powerful of reasons. As you continue in your LFS experience, you will discover the power that information and knowledge truly bring.

LFS Target Architectures
The primary target architecture of LFS is the 32-bit Intel CPU. If you have not built an LFS system before, you should probably start with that target. The 32-bit architecture is the most widely supported Linux system and is most compatible with both open source and proprietary software. On the other hand, the instructions in this book are known to work, with some modifications, with both Power PC and 64-bit AMD/Intel CPUs. To build a system that utilizes one of these CPUs, the main prerequisite, in addition to those on the next few pages, is an existing Linux system such as an earlier LFS installation, Ubuntu, Red Hat/Fedora, SuSE, or other distribution that targets the architecture that you have. Also note that a 32-bit distribution can be installed and used as a host system on a 64-bit AMD/Intel computer. Some other facts about 64-bit systems need to be added here. When compared to a 32-bit system, the sizes of executable programs are slightly larger and the execution speeds are only slightly faster. For example, in a test build of LFS-6.5 on a Core2Duo CPU based system, the following statistics were measured: Architecture Build Time 32-bit 198.5 minutes 64-bit 190.6 minutes Build Size 648 MB 709 MB

As you can see, the 64-bit build is only 4% faster and is 9% larger than the 32-bit build. The gain from going to a 64-bit system is relatively minimal. Of course, if you have more than 4GB of RAM or want to manipulate data that exceeds 4GB, the advantages of a 64-bit system are substantial.

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Linux From Scratch - Version 6.7 The default 64-bit build that results from LFS is considered a "pure" 64-bit system. That is, it supports 64-bit executables only. Building a "multi-lib" system requires compiling many applications twice, once for a 32-bit system and once for a 64-bit system. This is not directly supported in LFS because it would interfere with the educational objective of providing the instructions needed for a straightforward base Linux system. You can refer to the Cross Linux From Scratch project for this advanced topic. There is one last comment about 64-bit systems. There are some packages that cannot currently be built in a "pure" 64-bit system or require specialized build instructions. Generally, these packages have some embedded 32-bit specific assembly language instructions that fail when building on a 64-bit system. This includes some Xorg drivers from Beyond Linux From Scratch (BLFS). Many of these problems can be worked around, but may require some specialized procedures or patches.

LFS and Standards
The structure of LFS follows Linux standards as closely as possible. The primary standards are: • The Single UNIX Specification Version 3 (POSIX). Note: Free registration is required. • Filesystem Hierarchy Standard (FHS) • Linux Standard Base (LSB) Core Specification 4.0 The LSB has five separate standards: Core, C++, Desktop, Runtime Languages, and Printing. In addition to generic requirements there are also architecture specific requirements. LFS attempts to conform to the architectures discussed in the previous section.

Note
Many people do not agree with the requirements of the LSB. The main purpose of defining it is to ensure that proprietary software will be able to be installed and run properly on a compliant system. Since LFS is source based, the user has complete control over what packages are desired and many choose not to install some packages that are specified by the LSB. Creating a complete LFS system capable of passing the LSB certifications tests is possible, but not without many additional packages that are beyond the scope of LFS. Most of these additional packages have installation instructions in BLFS.

Rationale for Packages in the Book
As stated earlier, the goal of LFS is to build a complete and usable foundation-level system. This includes all packages needed to replicate itself while providing a relatively minimal base from which to customize a more complete system based on the choices of the user. This does not mean that LFS is the smallest system possible. Several important packages are included that are not strictly required. The lists below document the rationale for each package in the book. • Autoconf This package contains programs for producing shell scripts that can automatically configure source code from a developer's template. It is often needed to rebuild a package after updates to the build procedures. • Automake This package contains programs for generating Make files from a template. It is often needed to rebuild a package after updates to the build procedures. • Bash This package satisfies an LSB core requirement to provide a Bourne Shell interface to the system. It was chosen over other shell packages because of its common usage and extensive capabilities beyond basic shell functions. • Binutils This package contains a linker, an assembler, and other tools for handling object files. The programs in this package are needed to compile most of the packages in an LFS system and beyond. • Bison This package contains the GNU version of yacc (Yet Another Compiler Compiler) needed to build several other LFS programs. • Bzip2 This package contains programs for compressing and decompressing files. It is required to decompress many LFS packages. • Coreutils xi

Linux From Scratch - Version 6.7 This package contains a number of essential programs for viewing and manipulating files and directories. These programs are needed for command line file management, and are necessary for the installation procedures of every package in LFS. • DejaGNU This package contains a framework for testing other programs. It is only installed in the temporary toolchain. • Diffutils This package contains programs that show the differences between files or directories. These programs can be used to create patches, and are also used in many packages' build procedures. • Expect This package contains a program for carrying out scripted dialogues with other interactive programs. It is commonly used for testing other packages. It is only installed in the temporary toolchain. • E2fsprogs This package contains the utilities for handling the ext2, ext3 and ext4 file systems. These are the most common and thoroughly tested file systems that Linux supports. • File This package contains a utility for determining the type of a given file or files. A few packages need it to build. • Findutils This package contains programs to find files in a file system. It is used in many packages' build scripts. • Flex This package contains a utility for generating programs that recognize patterns in text. It is the GNU version of the lex (lexical analyzer) program. It is required to build several LFS packages. • Gawk This package contains programs for manipulating text files. It is the GNU version of awk (Aho-Weinberg-Kernighan). It is used in many other packages' build scripts. • Gcc This package is the Gnu Compiler Collection. It contains the C and C++ compilers as well as several others not built by LFS. • GDBM This package contains the GNU Database Manager library. It is used by one other LFS package, Man-DB. • Gettext This package contains utilities and libraries for internationalization and localization of numerous packages. • Glibc This package contains the main C library. Linux programs would not run without it. • GMP This package contains math libraries that provide useful functions for arbitrary precision arithmetic. It is required to build Gcc. • Grep

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Linux From Scratch - Version 6.7 This package contains programs for searching through files. These programs are used by most packages' build scripts. • Groff This package contains programs for processing and formatting text. One important function of these programs is to format man pages. • GRUB This package is the Grand Unified Boot Loader. It is one of several boot loaders available, but is the most flexible. • Gzip This package contains programs for compressing and decompressing files. It is needed to decompress many packages in LFS and beyond. • Iana-etc This package provides data for network services and protocols. It is needed to enable proper networking capabilities. • Inetutils This package contains programs for basic network administration. • IProute2 This package contains programs for basic and advanced IPv4 and IPv6 networking. It was chosen over the other common network tools package (net-tools) for its IPv6 capabilities. • Kbd This package contains key-table files, keyboard utilities for non-US keyboards, and a number of console fonts. • Less This package contains a very nice text file viewer that allows scrolling up or down when viewing a file. It is also used by Man-DB for viewing manpages. • Libtool This package contains the GNU generic library support script. It wraps the complexity of using shared libraries in a consistent, portable interface. It is needed by the test suites in other LFS packages. • Linux Kernel This package is the Operating System. It is the Linux in the GNU/Linux environment. • M4 This package contains a general text macro processor useful as a build tool for other programs. • Make This package contains a program for directing the building of packages. It is required by almost every package in LFS. • Man-DB This package contains programs for finding and viewing man pages. It was chosen instead of the man package due to superior internationalization capabilities. It supplies the man program.

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Linux From Scratch - Version 6.7 • Man-pages This package contains the actual contents of the basic Linux man pages. • Module-Init-Tools This package contains programs needed to administer Linux kernel modules. • MPC This package contains functions for the arithmetic of complex numbers. It is required by Gcc. • MPFR This package contains functions for multiple precision arithmetic. It is required by Gcc. • Ncurses This package contains libraries for terminal-independent handling of character screens. It is often used to provide cursor control for a menuing system. It is needed by a number of packages in LFS. • Patch This package contains a program for modifying or creating files by applying a patch file typically created by the diff program. It is needed by the build procedure for several LFS packages. • Perl This package is an interpreter for the runtime language PERL. It is needed for the installation and test suites of several LFS packages. • Pkg-config This package contains a tool for passing the include path and/or library paths to build tools during the configure and make processes. It is needed by many LFS packages. • Procps This package contains programs for monitoring processes. These programs are useful for system administration, and are also used by the LFS Bootscripts. • Psmisc This package contains programs for displaying information about running processes. These programs are useful for system administration. • Readline This package is a set of libraries that offers command-line editing and history capabilities. It is used by Bash. • Sed This package allows editing of text without opening it in a text editor. It is also needed by most LFS packages' configure scripts. • Shadow This package contains programs for handling passwords in a secure way. • Sysklogd This package contains programs for logging system messages, such as those given by the kernel or daemon processes when unusual events occur. • Sysvinit

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Linux From Scratch - Version 6.7 This package provides the init program, which is the parent of all other processes on the Linux system. • Tar This package provides archiving and extraction capabilities of virtually all packages used in LFS. • Tcl This package contains the Tool Command Language used in many test suites in LFS packages. It is only installed in the temporary toolchain. • Texinfo This package contains programs for reading, writing, and converting info pages. It is used in the installation procedures of many LFS packages. • Udev This package contains programs for dynamic creation of device nodes. It is an alternative to creating thousands of static devices in the /dev directory. • Util-linux-ng This package contains miscellaneous utility programs. Among them are utilities for handling file systems, consoles, partitions, and messages. • Vim This package contains an editor. It was chosen because of its compatibility with the classic vi editor and its huge number of powerful capabilities. An editor is a very personal choice for many users and any other editor could be substituted if desired. • Zlib This package contains compression and decompression routines used by some programs.

Prerequisites
Building an LFS system is not a simple task. It requires a certain level of existing knowledge of Unix system administration in order to resolve problems and correctly execute the commands listed. In particular, as an absolute minimum, you should already have the ability to use the command line (shell) to copy or move files and directories, list directory and file contents, and change the current directory. It is also expected that you have a reasonable knowledge of using and installing Linux software. Because the LFS book assumes at least this basic level of skill, the various LFS support forums are unlikely to be able to provide you with much assistance in these areas. You will find that your questions regarding such basic knowledge will likely go unanswered or you will simply be referred to the LFS essential pre-reading list. Before building an LFS system, we recommend reading the following HOWTOs: • Software-Building-HOWTO http://www.tldp.org/HOWTO/Software-Building-HOWTO.html This is a comprehensive guide to building and installing “generic” Unix software packages under Linux. Although it was written some time ago, it still provides a good summary of the basic techniques needed to build and install software. • The Linux Users' Guide http://www.linuxhq.com/guides/LUG/guide.html This guide covers the usage of assorted Linux software. This reference is also fairly old, but still valid.

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Linux From Scratch - Version 6.7 • The Essential Pre-Reading Hint http://www.linuxfromscratch.org/hints/downloads/files/essential_prereading.txt This is an LFS Hint written specifically for users new to Linux. It includes a list of links to excellent sources of information on a wide range of topics. Anyone attempting to install LFS should have an understanding of many of the topics in this hint.

Host System Requirements
Your host system should have the following software with the minimum versions indicated. This should not be an issue for most modern Linux distributions. Also note that many distributions will place software headers into separate packages, often in the form of “<package-name>-devel” or “<package-name>-dev”. Be sure to install those if your distribution provides them. Earlier versions of the listed software packages may work, but has not been tested. • • • • • • • • • • • • • Bash-3.2 (/bin/sh should be a symbolic or hard link to bash) Binutils-2.17 (Versions greater than 2.20.1 are not recommended as they have not been tested) Bison-2.3 (/usr/bin/yacc should be a link to bison or small script that executes bison) Bzip2-1.0.4 Coreutils-6.9 Diffutils-2.8.1 Findutils-4.2.31 Gawk-3.1.5 (/usr/bin/awk should be a link to gawk) Gcc-4.1.2 (Versions greater than 4.5.1 are not recommended as they have not been tested) Glibc-2.5.1 (Versions greater than 2.12.1 are not recommended as they have not been tested) Grep-2.5.1a Gzip-1.3.12 Linux Kernel-2.6.22.5 (having been compiled with GCC-4.1.2 or greater) The reason for the kernel version requirement is that we specify that version when building glibc in Chapter 6 at the recommendation of the developers. If the host kernel is either earlier than 2.6.22.5, or it was not compiled using a GCC-4.1.2 (or later) compiler, you will need to replace the kernel with one adhering to the specifications. There are two ways you can go about this. First, see if your Linux vendor provides a 2.6.22.5 or later kernel package. If so, you may wish to install it. If your vendor doesn't offer an acceptable kernel package, or you would prefer not to install it, you can compile a kernel yourself. Instructions for compiling the kernel and configuring the boot loader (assuming the host uses GRUB) are located in Chapter 8. M4-1.4.10 Make-3.81 Patch-2.5.4 Perl-5.8.8 Sed-4.1.5 Tar-1.18 Texinfo-4.9

• • • • • • •

Note that the symlinks mentioned above are required to build an LFS system using the instructions contained within this book. Symlinks that point to other software (such as dash, mawk, etc.) may work, but are not tested or supported by the LFS development team, and may require either deviation from the instructions or additional patches to some packages. xvi

Typography
To make things easier to follow, there are a few typographical conventions used throughout this book. This section contains some examples of the typographical format found throughout Linux From Scratch. ./configure --prefix=/usr This form of text is designed to be typed exactly as seen unless otherwise noted in the surrounding text. It is also used in the explanation sections to identify which of the commands is being referenced. In some cases, a logical line is extended to two or more physical lines with a backslash at the end of the line. CC="gcc -B/usr/bin/" ../binutils-2.18/configure \ --prefix=/tools --disable-nls --disable-werror Note that the backslash must be followed by an immediate return. Other whitespace characters like spaces or tab characters will create incorrect results. install-info: unknown option '--dir-file=/mnt/lfs/usr/info/dir' This form of text (fixed-width text) shows screen output, usually as the result of commands issued. This format is also used to show filenames, such as /etc/ld.so.conf. Emphasis This form of text is used for several purposes in the book. Its main purpose is to emphasize important points or items. http://www.linuxfromscratch.org/ This format is used for hyperlinks both within the LFS community and to external pages. It includes HOWTOs, download locations, and websites. cat > $LFS/etc/group << "EOF" root:x:0: bin:x:1: ...... EOF This format is used when creating configuration files. The first command tells the system to create the file $LFS/etc/group from whatever is typed on the following lines until the sequence End Of File (EOF) is encountered. Therefore, this entire section is generally typed as seen. <REPLACED TEXT> This format is used to encapsulate text that is not to be typed as seen or for copy-and-paste operations. [OPTIONAL TEXT] This format is used to encapsulate text that is optional. passwd(5) This format is used to refer to a specific manual (man) page. The number inside parentheses indicates a specific section inside the manuals. For example, passwd has two man pages. Per LFS installation instructions, those two man pages will be located at /usr/share/man/man1/passwd.1 and /usr/share/man/man5/passwd.5. When the book uses passwd(5) it is specifically referring to /usr/share/man/man5/passwd.5. man passwd xviii

Linux From Scratch - Version 6.7 will print the first man page it finds that matches “passwd”, which will be /usr/share/man/man1/passwd. 1. For this example, you will need to run man 5 passwd in order to read the specific page being referred to. It should be noted that most man pages do not have duplicate page names in different sections. Therefore, man <program name> is generally sufficient.

Structure
This book is divided into the following parts.

Part I - Introduction
Part I explains a few important notes on how to proceed with the LFS installation. This section also provides meta-information about the book.

Part II - Preparing for the Build
Part II describes how to prepare for the building process—making a partition, downloading the packages, and compiling temporary tools.

Part III - Building the LFS System
Part III guides the reader through the building of the LFS system—compiling and installing all the packages one by one, setting up the boot scripts, and installing the kernel. The resulting Linux system is the foundation on which other software can be built to expand the system as desired. At the end of this book, there is an easy to use reference listing all of the programs, libraries, and important files that have been installed.

Errata
The software used to create an LFS system is constantly being updated and enhanced. Security warnings and bug fixes may become available after the LFS book has been released. To check whether the package versions or instructions in this release of LFS need any modifications to accommodate security vulnerabilities or other bug fixes, please visit http://www.linuxfromscratch.org/lfs/errata/6.7/ before proceeding with your build. You should note any changes shown and apply them to the relevant section of the book as you progress with building the LFS system.

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Part I. Introduction

Linux From Scratch - Version 6.7

Chapter 1. Introduction
1.1. How to Build an LFS System
The LFS system will be built by using an already installed Linux distribution (such as Debian, Mandriva, Red Hat, or SUSE). This existing Linux system (the host) will be used as a starting point to provide necessary programs, including a compiler, linker, and shell, to build the new system. Select the “development” option during the distribution installation to be able to access these tools. As an alternative to installing a separate distribution onto your machine, you may wish to use the Linux From Scratch LiveCD or a LiveCD from a commercial distribution. The LFS LiveCD works well as a host system, providing all the tools you need to successfully follow the instructions in this book. The LiveCD version is behind the current book, but is still useful as a host for building the current book. The “-nosrc” or “-min” editions of the LiveCD are the most appropriate for building a current LFS system. For more information about the LFS LiveCD or to download a copy, visit http://www.linuxfromscratch.org/livecd/.

Note
The LFS LiveCD might not work on newer hardware configurations, failing to boot or failing to detect some devices such as some SATA hard drives. Chapter 2 of this book describes how to create a new Linux native partition and file system. This is the place where the new LFS system will be compiled and installed. Chapter 3 explains which packages and patches need to be downloaded to build an LFS system and how to store them on the new file system. Chapter 4 discusses the setup of an appropriate working environment. Please read Chapter 4 carefully as it explains several important issues you need be aware of before beginning to work your way through Chapter 5 and beyond. Chapter 5 explains the installation of a number of packages that will form the basic development suite (or toolchain) which is used to build the actual system in Chapter 6. Some of these packages are needed to resolve circular dependencies—for example, to compile a compiler, you need a compiler. Chapter 5 also shows you how to build a first pass of the toolchain, including Binutils and GCC (first pass basically means these two core packages will be reinstalled). The next step is to build Glibc, the C library. Glibc will be compiled by the toolchain programs built in the first pass. Then, a second pass of the toolchain will be built. This time, the toolchain will be dynamically linked against the newly built Glibc. The remaining Chapter 5 packages are built using this second pass toolchain. When this is done, the LFS installation process will no longer depend on the host distribution, with the exception of the running kernel. This effort to isolate the new system from the host distribution may seem excessive. A full technical explanation as to why this is done is provided in Section 5.2, “Toolchain Technical Notes”. In Chapter 6, the full LFS system is built. The chroot (change root) program is used to enter a virtual environment and start a new shell whose root directory will be set to the LFS partition. This is very similar to rebooting and instructing the kernel to mount the LFS partition as the root partition. The system does not actually reboot, but instead chroot's because creating a bootable system requires additional work which is not necessary just yet. The major advantage is that “chrooting” allows you to continue using the host system while LFS is being built. While waiting for package compilations to complete, you can continue using your computer as normal. To finish the installation, the LFS-Bootscripts are set up in Chapter 7, and the kernel and boot loader are set up in Chapter 8. Chapter 9 contains information on continuing the LFS experience beyond this book. After the steps in this book have been implemented, the computer will be ready to reboot into the new LFS system. 2

Linux From Scratch - Version 6.7 This is the process in a nutshell. Detailed information on each step is discussed in the following chapters and package descriptions. Items that may seem complicated will be clarified, and everything will fall into place as you embark on the LFS adventure.

1.2. What's new since the last release
Below is a list of package updates made since the previous release of the book.
Upgraded to:

1.3. Changelog
This is version 6.7 of the Linux From Scratch book, dated September 18, 2010. If this book is more than six months old, a newer and better version is probably already available. To find out, please check one of the mirrors via http://www. linuxfromscratch.org/mirrors.html. Below is a list of changes made since the previous release of the book.
Changelog Entries:

1.4. Resources
1.4.1. FAQ
If during the building of the LFS system you encounter any errors, have any questions, or think there is a typo in the book, please start by consulting the Frequently Asked Questions (FAQ) that is located at http://www.linuxfromscratch. org/faq/.

1.4.2. Mailing Lists
The linuxfromscratch.org server hosts a number of mailing lists used for the development of the LFS project. These lists include the main development and support lists, among others. If the FAQ does not solve the problem you are having, the next step would be to search the mailing lists at http://www.linuxfromscratch.org/search.html. For information on the different lists, how to subscribe, archive locations, and additional information, visit http://www. linuxfromscratch.org/mail.html.

1.4.3. IRC
Several members of the LFS community offer assistance on our community Internet Relay Chat (IRC) network. Before using this support, please make sure that your question is not already answered in the LFS FAQ or the mailing list archives. You can find the IRC network at irc.linuxfromscratch.org. The support channel is named #LFS-support. 9

Linux From Scratch - Version 6.7

1.4.4. Mirror Sites
The LFS project has a number of world-wide mirrors to make accessing the website and downloading the required packages more convenient. Please visit the LFS website at http://www.linuxfromscratch.org/mirrors.html for a list of current mirrors.

1.4.5. Contact Information
Please direct all your questions and comments to one of the LFS mailing lists (see above).

1.5. Help
If an issue or a question is encountered while working through this book, please check the FAQ page at http://www. linuxfromscratch.org/faq/#generalfaq. Questions are often already answered there. If your question is not answered on this page, try to find the source of the problem. The following hint will give you some guidance for troubleshooting: http://www.linuxfromscratch.org/hints/downloads/files/errors.txt. If you cannot find your problem listed in the FAQ, search the mailing lists at http://www.linuxfromscratch.org/search. html. We also have a wonderful LFS community that is willing to offer assistance through the mailing lists and IRC (see the Section 1.4, “Resources” section of this book). However, we get several support questions every day and many of them can be easily answered by going to the FAQ and by searching the mailing lists first. So, for us to offer the best assistance possible, you need to do some research on your own first. That allows us to focus on the more unusual support needs. If your searches do not produce a solution, please include all relevant information (mentioned below) in your request for help.

1.5.1. Things to Mention
Apart from a brief explanation of the problem being experienced, the essential things to include in any request for help are: • The version of the book being used (in this case 6.7) • The host distribution and version being used to create LFS • The output from the Section vii, “Host System Requirements” [xvii] • The package or section the problem was encountered in • The exact error message or symptom being received • Note whether you have deviated from the book at all

Note
Deviating from this book does not mean that we will not help you. After all, LFS is about personal preference. Being upfront about any changes to the established procedure helps us evaluate and determine possible causes of your problem.

1.5.2. Configure Script Problems
If something goes wrong while running the configure script, review the config.log file. This file may contain errors encountered during configure which were not printed to the screen. Include the relevant lines if you need to ask for help. 10

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1.5.3. Compilation Problems
Both the screen output and the contents of various files are useful in determining the cause of compilation problems. The screen output from the configure script and the make run can be helpful. It is not necessary to include the entire output, but do include enough of the relevant information. Below is an example of the type of information to include from the screen output from make: gcc -DALIASPATH=\"/mnt/lfs/usr/share/locale:.\" -DLOCALEDIR=\"/mnt/lfs/usr/share/locale\" -DLIBDIR=\"/mnt/lfs/usr/lib\" -DINCLUDEDIR=\"/mnt/lfs/usr/include\" -DHAVE_CONFIG_H -I. -I. -g -O2 -c getopt1.c gcc -g -O2 -static -o make ar.o arscan.o commands.o dir.o expand.o file.o function.o getopt.o implicit.o job.o main.o misc.o read.o remake.o rule.o signame.o variable.o vpath.o default.o remote-stub.o version.o opt1.o -lutil job.o: In function `load_too_high': /lfs/tmp/make-3.79.1/job.c:1565: undefined reference to `getloadavg' collect2: ld returned 1 exit status make[2]: *** [make] Error 1 make[2]: Leaving directory `/lfs/tmp/make-3.79.1' make[1]: *** [all-recursive] Error 1 make[1]: Leaving directory `/lfs/tmp/make-3.79.1' make: *** [all-recursive-am] Error 2 In this case, many people would just include the bottom section: make [2]: *** [make] Error 1 This is not enough information to properly diagnose the problem because it only notes that something went wrong, not what went wrong. The entire section, as in the example above, is what should be saved because it includes the command that was executed and the associated error message(s). An excellent article about asking for help on the Internet is available online at http://catb. org/~esr/faqs/smart-questions.html. Read and follow the hints in this document to increase the likelihood of getting the help you need.

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Part II. Preparing for the Build

Linux From Scratch - Version 6.7

Chapter 2. Preparing a New Partition
2.1. Introduction
In this chapter, the partition which will host the LFS system is prepared. We will create the partition itself, create a file system on it, and mount it.

2.2. Creating a New Partition
Like most other operating systems, LFS is usually installed on a dedicated partition. The recommended approach to building an LFS system is to use an available empty partition or, if you have enough unpartitioned space, to create one. A minimal system requires a partition of around 1.3 gigabytes (GB). This is enough to store all the source tarballs and compile the packages. However, if the LFS system is intended to be the primary Linux system, additional software will probably be installed which will require additional space (2-3 GB). The LFS system itself will not take up this much room. A large portion of this requirement is to provide sufficient free temporary storage. Compiling packages can require a lot of disk space which will be reclaimed after the package is installed. Because there is not always enough Random Access Memory (RAM) available for compilation processes, it is a good idea to use a small disk partition as swap space. This is used by the kernel to store seldom-used data and leave more memory available for active processes. The swap partition for an LFS system can be the same as the one used by the host system, in which case it is not necessary to create another one. Start a disk partitioning program such as cfdisk or fdisk with a command line option naming the hard disk on which the new partition will be created—for example /dev/hda for the primary Integrated Drive Electronics (IDE) disk. Create a Linux native partition and a swap partition, if needed. Please refer to cfdisk(8) or fdisk(8) if you do not yet know how to use the programs. Remember the designation of the new partition (e.g., hda5). This book will refer to this as the LFS partition. Also remember the designation of the swap partition. These names will be needed later for the /etc/fstab file.

2.2.1. Other Partition Issues
Requests for advice on system partitioning are often posted on the LFS mailing lists. This is a highly subjective topic. The default for most distributions is to use the entire drive with the exception of one small swap partition. This is not optimal for LFS for several reasons. It reduces flexibility, makes sharing of data across multiple distributions or LFS builds more difficult, makes backups more time consuming, and can waste disk space through inefficient allocation of file system structures.

2.2.1.1. The Root Partition
A root LFS partition (not to be confused with the /root directory) of ten gigabytes is a good compromise for most systems. It provides enough space to build LFS and most of BLFS, but is small enough so that multiple partitions can be easily created for experimentation.

2.2.1.2. The Swap Partition
Most distributions automatically create a swap partition. Generally the recommended size of the swap partition is about twice the amount of physical RAM, however this is rarely needed. If disk space is limited, hold the swap partition to two gigabytes and monitor the amount of disk swapping. 13

Linux From Scratch - Version 6.7 Swapping is never good. Generally you can tell if a system is swapping by just listening to disk activity and observing how the system reacts to commands. The first reaction to swapping should be to check for an unreasonable command such as trying to edit a five gigabyte file. If swapping becomes a normal occurance, the best solution is to purchase more RAM for your system.

2.2.1.3. Convenience Partitions
There are several other partitions that are not required, but should be considered when designing a disk layout. The following list is not comprehensive, but is meant as a guide. • /boot – Highly recommended. Use this partition to store kernels and other booting information. To minimize potential boot problems with larger disks, make this the first physical partition on your first disk drive. A partition size of 100 megabytes is quite adequate. • /home – Highly recommended. Share your home directory and user customization across multiple distributions or LFS builds. The size is generally fairly large and depends on available disk space. • /usr – A separate /usr partition is generally used if providing a server for a thin client or diskless workstation. It is normally not needed for LFS. A size of five gigabytes will handle most installations. • /opt – This directory is most useful for BLFS where multiple installations of large packages like Gnome or KDE can be installed without embedding the files in the /usr hierarchy. If used, five to ten gigabytes is generally adequate. • /tmp – A separate /tmp directory is rare, but useful if configuring a thin client. This partition, if used, will usually not need to exceed a couple of gigabytes. • /usr/src – This partition is very useful for providing a location to store BLFS source files and share them across LFS builds. It can also be used as a location for building BLFS packages. A reasonably large partition of 30-50 gigabytes allows plenty of room. Any separate partition that you want automatically mounted upon boot needs to be specified in the /etc/fstab. Details about how to specify partitions will be discussed in Section 8.2, “Creating the /etc/fstab File”.

2.3. Creating a File System on the Partition
Now that a blank partition has been set up, the file system can be created. The most widely-used system in the Linux world is the second extended file system (ext2), but with newer high-capacity hard disks, journaling file systems are becoming increasingly popular. The third extended filesystem (ext3) is a widely used enhancement to ext2, which adds journaling capabilities and is compatible with the E2fsprogs utilities. We will create an ext3 file system. Instructions for creating other file systems can be found at http://www.linuxfromscratch. org/blfs/view/svn/postlfs/filesystems.html. To create an ext3 file system on the LFS partition, run the following: mke2fs -jv /dev/<xxx> Replace <xxx> with the name of the LFS partition (hda5 in our previous example).

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Note
Some host distributions use custom features in their filesystem creation tools (E2fsprogs). This can cause problems when booting into your new LFS in Chapter 9, as those features will not be supported by the LFS-installed E2fsprogs; you will get an error similar to “unsupported filesystem features, upgrade your e2fsprogs”. To check if your host system uses custom enhancements, run the following command: debugfs -R feature /dev/<xxx> If the output contains features other than has_journal, ext_attr, resize_inode, dir_index, filetype, sparse_super, large_file or needs_recovery, then your host system may have custom enhancements. In that case, to avoid later problems, you should compile the stock E2fsprogs package and use the resulting binaries to re-create the filesystem on your LFS partition: cd /tmp tar -xzvf /path/to/sources/e2fsprogs-1.41.12.tar.gz cd e2fsprogs-1.41.12 mkdir -v build cd build ../configure make #note that we intentionally don't 'make install' here! ./misc/mke2fs -jv /dev/<xxx> cd /tmp rm -rfv e2fsprogs-1.41.12 If you are using an existing swap partition, there is no need to format it. If a new it will need to be initialized with this command: mkswap /dev/<yyy> Replace <yyy> with the name of the swap partition. swap partition was created,

2.4. Mounting the New Partition
Now that a file system has been created, the partition needs to be made accessible. In order to do this, the partition needs to be mounted at a chosen mount point. For the purposes of this book, it is assumed that the file system is mounted under /mnt/lfs, but the directory choice is up to you. Choose a mount point and assign it to the LFS environment variable by running: export LFS=/mnt/lfs Next, create the mount point and mount the LFS file system by running: mkdir -pv $LFS mount -v -t ext3 /dev/<xxx> $LFS Replace <xxx> with the designation of the LFS partition. 15

Replace <xxx> and <yyy> with the appropriate partition names. Ensure that this new partition is not mounted with permissions that are too restrictive (such as the nosuid, nodev, or noatime options). Run the mount command without any parameters to see what options are set for the mounted LFS partition. If nosuid, nodev, and/or noatime are set, the partition will need to be remounted. If you are using a swap partition, ensure that it is enabled using the swapon command: /sbin/swapon -v /dev/<zzz> Replace <zzz> with the name of the swap partition. Now that there is an established place to work, it is time to download the packages.

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Chapter 3. Packages and Patches
3.1. Introduction
This chapter includes a list of packages that need to be downloaded in order to build a basic Linux system. The listed version numbers correspond to versions of the software that are known to work, and this book is based on their use. We highly recommend against using newer versions because the build commands for one version may not work with a newer version. The newest package versions may also have problems that require work-arounds. These work-arounds will be developed and stabilized in the development version of the book. Download locations may not always be accessible. If a download location has changed since this book was published, Google (http://www.google.com/) provides a useful search engine for most packages. If this search is unsuccessful, try one of the alternative means of downloading discussed at http://www.linuxfromscratch. org/lfs/packages.html#packages. Downloaded packages and patches will need to be stored somewhere that is conveniently available throughout the entire build. A working directory is also required to unpack the sources and build them. $LFS/sources can be used both as the place to store the tarballs and patches and as a working directory. By using this directory, the required elements will be located on the LFS partition and will be available during all stages of the building process. To create this directory, execute the following command, as user root, before starting the download session: mkdir -v $LFS/sources Make this directory writable and sticky. “Sticky” means that even if multiple users have write permission on a directory, only the owner of a file can delete the file within a sticky directory. The following command will enable the write and sticky modes: chmod -v a+wt $LFS/sources An easy way to download all of the packages and patches is by using wget-list as an input to wget.

Note
File (5.04) may no longer be available at the listed location. The site administrators of the master download location occasionally remove older versions when new ones are released. An alternative download location that may have the correct version available can also be found at: http://www. linuxfromscratch.org/lfs/download.html#ftp. 18

Note
The Linux kernel is updated relatively often, many times due to discoveries of security vulnerabilities. The latest available 2.6.35.x kernel version should be used, unless the errata page says otherwise. For users with limited speed or expensive bandwidth who wish to update the Linux kernel, a baseline version of the package and patches can be downloaded separately. This may save some time or cost for a subsequent patch level upgrade within a minor release. 20

3.3. Needed Patches
In addition to the packages, several patches are also required. These patches correct any mistakes in the packages that should be fixed by the maintainer. The patches also make small modifications to make the packages easier to work with. The following patches will be needed to build an LFS system: • Bash Upstream Fixes Patch - 5.1 KB: Download: http://www.linuxfromscratch.org/patches/lfs/6.7/bash-4.1-fixes-2.patch MD5 sum: 7813f0e42d41dc4443dc3d161ad24987 • Bzip2 Documentation Patch - 1.6 KB: Download: http://www.linuxfromscratch.org/patches/lfs/6.7/bzip2-1.0.5-install_docs-1.patch MD5 sum: 6a5ac7e89b791aae556de0f745916f7f • Bzip2 Version Fixes Patch - 5.3 KB: Download: http://www.linuxfromscratch.org/patches/lfs/6.7/bzip2-1.0.5-version_fixes-1.patch MD5 sum: 5ef00b9da463b399f3d67ecfa276e7ea 23

Linux From Scratch - Version 6.7 Total size of these patches: about 174.1 KB In addition to the above required patches, there exist a number of optional patches created by the LFS community. These optional patches solve minor problems or enable functionality that is not enabled by default. Feel free to peruse the patches database located at http://www.linuxfromscratch.org/patches/downloads/ and acquire any additional patches to suit your system needs.

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Chapter 4. Final Preparations
4.1. About $LFS
Throughout this book, the environment variable LFS will be used. It is paramount that this variable is always defined. It should be set to the mount point chosen for the LFS partition. Check that the LFS variable is set up properly with: echo $LFS Make sure the output shows the path to the LFS partition's mount point, which is /mnt/lfs if the provided example was followed. If the output is incorrect, the variable can be set with: export LFS=/mnt/lfs Having this variable set is beneficial in that commands such as mkdir $LFS/tools can be typed literally. The shell will automatically replace “$LFS” with “/mnt/lfs” (or whatever the variable was set to) when it processes the command line. Do not forget to check that $LFS is set whenever you leave and reenter the current working environment (as when doing a su to root or another user).

4.2. Creating the $LFS/tools Directory
All programs compiled in Chapter 5 will be installed under $LFS/tools to keep them separate from the programs compiled in Chapter 6. The programs compiled here are temporary tools and will not be a part of the final LFS system. By keeping these programs in a separate directory, they can easily be discarded later after their use. This also prevents these programs from ending up in the host production directories (easy to do by accident in Chapter 5). Create the required directory by running the following as root: mkdir -v $LFS/tools The next step is to create a /tools symlink on the host system. This will point to the newly-created directory on the LFS partition. Run this command as root as well: ln -sv $LFS/tools /

Note
The above command is correct. The ln command has a few syntactic variations, so be sure to check info coreutils ln and ln(1) before reporting what you may think is an error. The created symlink enables the toolchain to be compiled so that it always refers to /tools, meaning that the compiler, assembler, and linker will work both in this chapter (when we are still using some tools from the host) and in the next (when we are “chrooted” to the LFS partition).

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4.3. Adding the LFS User
When logged in as user root, making a single mistake can damage or destroy a system. Therefore, we recommend building the packages in this chapter as an unprivileged user. You could use your own user name, but to make it easier to set up a clean working environment, create a new user called lfs as a member of a new group (also named lfs) and use this user during the installation process. As root, issue the following commands to add the new user: groupadd lfs useradd -s /bin/bash -g lfs -m -k /dev/null lfs
The meaning of the command line options:

-s /bin/bash This makes bash the default shell for user lfs. -g lfs This option adds user lfs to group lfs. -m This creates a home directory for lfs. -k /dev/null This parameter prevents possible copying of files from a skeleton directory (default is /etc/skel) by changing the input location to the special null device. lfs This is the actual name for the created group and user. To log in as lfs (as opposed to switching to user lfs when logged in as root, which does not require the lfs user to have a password), give lfs a password: passwd lfs Grant lfs full access to $LFS/tools by making lfs the directory owner: chown -v lfs $LFS/tools If a separate working directory was created as suggested, give user lfs ownership of this directory: chown -v lfs $LFS/sources Next, login as user lfs. This can be done via a virtual console, through a display manager, or with the following substitute user command: su - lfs The “-” instructs su to start a login shell as opposed to a non-login shell. The difference between these two types of shells can be found in detail in bash(1) and info bash.

4.4. Setting Up the Environment
Set up a good working environment by creating two new startup files for the bash shell. While logged in as user lfs, issue the following command to create a new .bash_profile: cat > ~/.bash_profile << "EOF" exec env -i HOME=$HOME TERM=$TERM PS1='\u:\w\$ ' /bin/bash EOF 27

Linux From Scratch - Version 6.7 When logged on as user lfs, the initial shell is usually a login shell which reads the /etc/profile of the host (probably containing some settings and environment variables) and then .bash_profile. The exec env -i.../bin/bash command in the .bash_profile file replaces the running shell with a new one with a completely empty environment, except for the HOME, TERM, and PS1 variables. This ensures that no unwanted and potentially hazardous environment variables from the host system leak into the build environment. The technique used here achieves the goal of ensuring a clean environment. The new instance of the shell is a non-login shell, which does not read the /etc/profile or .bash_profile files, but rather reads the .bashrc file instead. Create the .bashrc file now: cat > ~/.bashrc << "EOF" set +h umask 022 LFS=/mnt/lfs LC_ALL=POSIX LFS_TGT=$(uname -m)-lfs-linux-gnu PATH=/tools/bin:/bin:/usr/bin export LFS LC_ALL LFS_TGT PATH EOF The set +h command turns off bash's hash function. Hashing is ordinarily a useful feature—bash uses a hash table to remember the full path of executable files to avoid searching the PATH time and again to find the same executable. However, the new tools should be used as soon as they are installed. By switching off the hash function, the shell will always search the PATH when a program is to be run. As such, the shell will find the newly compiled tools in $LFS/tools as soon as they are available without remembering a previous version of the same program in a different location. Setting the user file-creation mask (umask) to 022 ensures that newly created files and directories are only writable by their owner, but are readable and executable by anyone (assuming default modes are used by the open(2) system call, new files will end up with permission mode 644 and directories with mode 755). The LFS variable should be set to the chosen mount point. The LC_ALL variable controls the localization of certain programs, making their messages follow the conventions of a specified country. If the host system uses a version of Glibc older than 2.2.4, having LC_ALL set to something other than “POSIX” or “C” (during this chapter) may cause issues if you exit the chroot environment and wish to return later. Setting LC_ALL to “POSIX” or “C” (the two are equivalent) ensures that everything will work as expected in the chroot environment. The LFS_TGT variable sets a non-default, but compatible machine description for use when building our cross compiler and linker and when cross compiling our temporary toolchain. More information is contained in Section 5.2, “Toolchain Technical Notes”. By putting /tools/bin ahead of the standard PATH, all the programs installed in Chapter 5 are picked up by the shell immediately after their installation. This, combined with turning off hashing, limits the risk that old programs are used from the host when the same programs are available in the chapter 5 environment. Finally, to have the environment fully prepared for building the temporary tools, source the just-created user profile: source ~/.bash_profile 28

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4.5. About SBUs
Many people would like to know beforehand approximately how long it takes to compile and install each package. Because Linux From Scratch can be built on many different systems, it is impossible to provide accurate time estimates. The biggest package (Glibc) will take approximately 20 minutes on the fastest systems, but could take up to three days on slower systems! Instead of providing actual times, the Standard Build Unit (SBU) measure will be used instead. The SBU measure works as follows. The first package to be compiled from this book is Binutils in Chapter 5. The time it takes to compile this package is what will be referred to as the Standard Build Unit or SBU. All other compile times will be expressed relative to this time. For example, consider a package whose compilation time is 4.5 SBUs. This means that if a system took 10 minutes to compile and install the first pass of Binutils, it will take approximately 45 minutes to build this example package. Fortunately, most build times are shorter than the one for Binutils. In general, SBUs are not entirely accurate because they depend on many factors, including the host system's version of GCC. They are provided here to give an estimate of how long it might take to install a package, but the numbers can vary by as much as dozens of minutes in some cases. To view actual timings for a number of specific machines, we recommend The LinuxFromScratch SBU Home Page at http://www.linuxfromscratch.org/~sbu/.

Note
For many modern systems with multiple processors (or cores) the compilation time for a package can be reduced by performing a "parallel make" by either setting an environment variable or telling the make program how many processors are available. For instance, a Core2Duo can support two simultaneous processes with: export MAKEFLAGS='-j 2' or just building with: make -j2 When multiple processors are used in this way, the SBU units in the book will vary even more than they normally would. Analyzing the output of the build process will also be more difficult because the lines of different processes will be interleaved. If you run into a problem with a build step, revert back to a single processor build to properly analyze the error messages.

4.6. About the Test Suites
Most packages provide a test suite. Running the test suite for a newly built package is a good idea because it can provide a “sanity check” indicating that everything compiled correctly. A test suite that passes its set of checks usually proves that the package is functioning as the developer intended. It does not, however, guarantee that the package is totally bug free. Some test suites are more important than others. For example, the test suites for the core toolchain packages—GCC, Binutils, and Glibc—are of the utmost importance due to their central role in a properly functioning system. The test suites for GCC and Glibc can take a very long time to complete, especially on slower hardware, but are strongly recommended. 29

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Note
Experience has shown that there is little to be gained from running the test suites in Chapter 5. There can be no escaping the fact that the host system always exerts some influence on the tests in that chapter, often causing inexplicable failures. Because the tools built in Chapter 5 are temporary and eventually discarded, we do not recommend running the test suites in Chapter 5 for the average reader. The instructions for running those test suites are provided for the benefit of testers and developers, but they are strictly optional. A common issue with running the test suites for Binutils and GCC is running out of pseudo terminals (PTYs). This can result in a high number of failing tests. This may happen for several reasons, but the most likely cause is that the host system does not have the devpts file system set up correctly. This issue is discussed in greater detail at http://www.linuxfromscratch.org//lfs/faq.html#no-ptys. Sometimes package test suites will fail, but for reasons which the developers are aware of and have deemed non-critical. Consult the logs located at http://www.linuxfromscratch.org/lfs/build-logs/6.7/ to verify whether or not these failures are expected. This site is valid for all tests throughout this book.

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Chapter 5. Constructing a Temporary System
5.1. Introduction
This chapter shows how to build a minimal Linux system. This system will contain just enough tools to start constructing the final LFS system in Chapter 6 and allow a working environment with more user convenience than a minimum environment would. There are two steps in building this minimal system. The first step is to build a new and host-independent toolchain (compiler, assembler, linker, libraries, and a few useful utilities). The second step uses this toolchain to build the other essential tools. The files compiled in this chapter will be installed under the $LFS/tools directory to keep them separate from the files installed in the next chapter and the host production directories. Since the packages compiled here are temporary, we do not want them to pollute the soon-to-be LFS system.

5.2. Toolchain Technical Notes
This section explains some of the rationale and technical details behind the overall build method. It is not essential to immediately understand everything in this section. Most of this information will be clearer after performing an actual build. This section can be referred to at any time during the process. The overall goal of Chapter 5 is to produce a temporary area that contains a known-good set of tools that can be isolated from the host system. By using chroot, the commands in the remaining chapters will be contained within that environment, ensuring a clean, trouble-free build of the target LFS system. The build process has been designed to minimize the risks for new readers and to provide the most educational value at the same time.

Important
Before continuing, be aware of the name of the working platform, often referred to as the target triplet. A simple way to determine the name of the target triplet is to run the config.guess script that comes with the source for many packages. Unpack the Binutils sources and run the script: ./config.guess and note the output. For example, for a modern 32-bit Intel processor the output will likely be i686-pc-linux-gnu. Also be aware of the name of the platform's dynamic linker, often referred to as the dynamic loader (not to be confused with the standard linker ld that is part of Binutils). The dynamic linker provided by Glibc finds and loads the shared libraries needed by a program, prepares the program to run, and then runs it. The name of the dynamic linker for a 32-bit Intel machine will be ld-linux.so.2. A sure-fire way to determine the name of the dynamic linker is to inspect a random binary from the host system by running: readelf -l <name of binary> | grep interpreter and noting the output. The authoritative reference covering all platforms is in the shlib-versions file in the root of the Glibc source tree. Some key technical points of how the Chapter 5 build method works: • Slightly adjusting the name of the working platform, by changing the "vendor" field target triplet by way of the LFS_TGT variable, ensures that the first build of Binutils and GCC produces a compatible cross-linker and cross-compiler. Instead of producing binaries for another architecture, the cross-linker and cross-compiler will produce binaries compatible with the current hardware. 31

Linux From Scratch - Version 6.7 • The temporary libraries are cross-compiled. Because a cross-compiler by its nature cannot rely on anything from its host system, this method removes potential contamination of the target system by lessening the chance of headers or libraries from the host being incorporated into the new tools. Cross-compilation also allows for the possibility of building both 32-bit and 64-bit libraries on 64-bit capable hardware. • Careful manipulation of gcc's specs file tells the compiler which target dynamic linker will be used Binutils is installed first because the configure runs of both GCC and Glibc perform various feature tests on the assembler and linker to determine which software features to enable or disable. This is more important than one might first realize. An incorrectly configured GCC or Glibc can result in a subtly broken toolchain, where the impact of such breakage might not show up until near the end of the build of an entire distribution. A test suite failure will usually highlight this error before too much additional work is performed. Binutils installs its assembler and linker in two locations, /tools/bin and /tools/$LFS_TGT/bin. The tools in one location are hard linked to the other. An important facet of the linker is its library search order. Detailed information can be obtained from ld by passing it the --verbose flag. For example, an ld --verbose | grep SEARCH will illustrate the current search paths and their order. It shows which files are linked by ld by compiling a dummy program and passing the --verbose switch to the linker. For example, gcc dummy.c -Wl,--verbose 2>&1 | grep succeeded will show all the files successfully opened during the linking. The next package installed is GCC. An example of what can be seen during its run of configure is: checking what assembler to use... /tools/i686-lfs-linux-gnu/bin/as checking what linker to use... /tools/i686-lfs-linux-gnu/bin/ld This is important for the reasons mentioned above. It also demonstrates that GCC's configure script does not search the PATH directories to find which tools to use. However, during the actual operation of gcc itself, the same search paths are not necessarily used. To find out which standard linker gcc will use, run: gcc -print-prog-name=ld. Detailed information can be obtained from gcc by passing it the -v command line option while compiling a dummy program. For example, gcc -v dummy.c will show detailed information about the preprocessor, compilation, and assembly stages, including gcc's included search paths and their order. The next package installed is Glibc. The most important considerations for building Glibc are the compiler, binary tools, and kernel headers. The compiler is generally not an issue since Glibc will always use the compiler relating to the --host parameter passed to its configure script, e.g. in our case, i686-lfs-linux-gnu-gcc. The binary tools and kernel headers can be a bit more complicated. Therefore, take no risks and use the available configure switches to enforce the correct selections. After the run of configure, check the contents of the config.make file in the glibc-build directory for all important details. Note the use of CC="i686-lfs-gnu-gcc" to control which binary tools are used and the use of the -nostdinc and -isystem flags to control the compiler's include search path. These items highlight an important aspect of the Glibc package—it is very self-sufficient in terms of its build machinery and generally does not rely on toolchain defaults. After the Glibc installation, change gcc's specs file to point to the new dynamic linker in /tools/lib. This last step is vital in ensuring that searching and linking take place only within the /tools prefix. A hard-wired path to a dynamic linker is embedded into every Executable and Link Format (ELF)-shared executable. This can be inspected by running: readelf -l <name of binary> | grep interpreter. Amending gcc's specs file ensures that every program compiled from here through the end of this chapter will use the new dynamic linker in /tools/lib. For the second pass of GCC, its sources also need to be modified to tell GCC to use the new dynamic linker. Failure to do so will result in the GCC programs themselves having the name of the dynamic linker from the host system's /lib directory embedded into them, which would defeat the goal of getting away from the host. 32

Linux From Scratch - Version 6.7 During the second pass of Binutils, we are able to utilize the --with-lib-path configure switch to control ld's library search path. From this point onwards, the core toolchain is self-contained and self-hosted. The remainder of the Chapter 5 packages all build against the new Glibc in /tools. Upon entering the chroot environment in Chapter 6, the first major package to be installed is Glibc, due to its self-sufficient nature mentioned above. Once this Glibc is installed into /usr, we will perform a quick changeover of the toolchain defaults, and then proceed in building the rest of the target LFS system.

5.3. General Compilation Instructions
When building packages there are several assumptions made within the instructions: • Several of the packages are patched before compilation, but only when the patch is needed to circumvent a problem. A patch is often needed in both this and the next chapter, but sometimes in only one or the other. Therefore, do not be concerned if instructions for a downloaded patch seem to be missing. Warning messages about offset or fuzz may also be encountered when applying a patch. Do not worry about these warnings, as the patch was still successfully applied. • During the compilation of most packages, there will be several warnings that scroll by on the screen. These are normal and can safely be ignored. These warnings are as they appear—warnings about deprecated, but not invalid, use of the C or C++ syntax. C standards change fairly often, and some packages still use the older standard. This is not a problem, but does prompt the warning.

Important
After installing each package, delete its source and build directories, unless specifically instructed otherwise. Deleting the sources prevents mis-configuration when the same package is reinstalled later. • Check one last time that the LFS environment variable is set up properly: echo $LFS Make sure the output shows the path to the LFS partition's mount point, which is /mnt/lfs, using our example. • Finally, two last important items must be emphasized:

Important
The build instructions assume that the bash shell is in use.

Important
Before issuing the build instructions for a package, the package should be unpacked as user lfs, and a cd into the created directory should be performed.

33

Linux From Scratch - Version 6.7 To re-emphasize the build process: 1. Place all the sources and patches in a directory that will be accessible from the chroot envronment such as /mnt/lfs/sources/. Do not put sources in /mnt/lfs/tools/. 2. Change to the sources directory. 3. For each package: a. Using the tar program, extract the package to be built. b. Change to the directory created when the package was extracted. c. Follow the book's instructions for building the package. d. Change back to the sources directory. e. Delete the extracted source directory and any <package>-build directories that were created in the build process.

5.4.1. Installation of Cross Binutils
Note
Go back and re-read the notes in the previous section. Understanding the notes labeled important will save you a lot of problems later. It is important that Binutils be the first package compiled because both Glibc and GCC perform various tests on the available linker and assembler to determine which of their own features to enable. The Binutils documentation recommends building Binutils outside of the source directory in a dedicated build directory: mkdir -v ../binutils-build cd ../binutils-build

Note
In order for the SBU values listed in the rest of the book to be of any use, measure the time it takes to build this package from the configuration, up to and including the first install. To achieve this easily, wrap the three commands in a time command like this: time { ./configure ... && make && make install; }.

--target=$LFS_TGT Because the machine description in the LFS_TGT variable is slightly different than the value returned by the config.guess script, this switch will tell the configure script to adjust Binutil's build system for building a cross linker. --prefix=/tools This tells the configure script to prepare to install the Binutils programs in the /tools directory. --disable-nls This disables internationalization as i18n is not needed for the temporary tools. 35

Linux From Scratch - Version 6.7 --disable-werror This prevents the build from stopping in the event that there are warnings from the host's compiler. Continue with compiling the package: make Compilation is now complete. Ordinarily we would now run the test suite, but at this early stage the test suite framework (Tcl, Expect, and DejaGNU) is not yet in place. The benefits of running the tests at this point are minimal since the programs from this first pass will soon be replaced by those from the second. If building on x86_64, create a symlink to ensure the sanity of the toolchain: case $(uname -m) in x86_64) mkdir -v /tools/lib && ln -sv lib /tools/lib64 ;; esac Install the package: make install Details on this package are located in Section 6.12.2, “Contents of Binutils.”

--disable-shared This switch forces GCC to link its internal libraries statically. We do this to avoid possible issues with the host system. --disable-decimal-float, --disable-threads, --disable-libmudflap, --disable-libssp, --disable-libgomp These switches disable support for the decimal floating point extension, threading, libmudflap, libssp and libgomp respectively. These features will fail to compile when building a cross-compiler and are not necessary for the task of cross-compiling the temporary libc. --disable-multilib On x86_64, LFS does not yet support a multilib configuration. This switch is harmless for x86. --enable-languages=c This option ensures that only the C compiler is built. This is the only language needed now. 37

Linux From Scratch - Version 6.7 --with-gmp-include=... This option tells GCC where the GMP headers are located. --with-gmp-lib=... This option tells GCC where the GMP library is located. --without-ppl, --without-cloog These switches prevent GCC from building against the PPL and CLooG libraries which may be present on the host system, but will not be available in the chroot environment. Compile GCC by running: make Compilation is now complete. At this point, the test suite would normally be run, but, as mentioned before, the test suite framework is not in place yet. The benefits of running the tests at this point are minimal since the programs from this first pass will soon be replaced. Install the package: make install Using --disable-shared means that the libgcc_eh.a file isn't created and installed. The Glibc package depends on this library as it uses -lgcc_eh within its build system. This dependency can be satisfied by creating a symlink to libgcc.a, since that file will end up containing the objects normally contained in libgcc_eh.a: ln -vs libgcc.a `$LFS_TGT-gcc -print-libgcc-file-name | \ sed 's/libgcc/&_eh/'` Details on this package are located in Section 6.16.2, “Contents of GCC.”

5.6.1. Installation of Linux API Headers
The Linux kernel needs to expose an Application Programming Interface (API) for the system's C library (Glibc in LFS) to use. This is done by way of sanitizing various C header files that are shipped in the Linux kernel source tarball. Make sure there are no stale files and dependencies lying around from previous activity: make mrproper Now test and extract the user-visible kernel headers from the source. They are placed in an intermediate local directory and copied to the needed location because the extraction process removes any existing files in the target directory. make headers_check make INSTALL_HDR_PATH=dest headers_install cp -rv dest/include/* /tools/include Details on this package are located in Section 6.7.2, “Contents of Linux API Headers.”

5.7.1. Installation of Glibc
Fix a bug that prevents Glibc from building with GCC-4.5.1: patch -Np1 -i ../glibc-2.12.1-gcc_fix-1.patch Fix a bug that prevents Glibc from building with versions of Make newer than 3.81. patch -Np1 -i ../glibc-2.12.1-makefile_fix-1.patch The Glibc documentation recommends building Glibc outside of the source directory in a dedicated build directory: mkdir -v ../glibc-build cd ../glibc-build Because Glibc no longer supports i386, its developers say to use the compiler flag -march=i486 when building it for x86 machines. There are several ways to accomplish that, but testing shows that the flag is best placed inside the build variable “CFLAGS”. Instead of overriding completely what Glibc's internal build system uses for CFLAGS, append the new flag to the existing contents of CFLAGS by making use of the special file configparms. The -mtune=native flag is also necessary to reset a reasonable value for -mtune that is changed when setting -march. case `uname -m` in i?86) echo "CFLAGS += -march=i486 -mtune=native" > configparms ;; esac Next, prepare Glibc for compilation: ../glibc-2.12.1/configure --prefix=/tools \ --host=$LFS_TGT --build=$(../glibc-2.12.1/scripts/config.guess) \ --disable-profile --enable-add-ons \ --enable-kernel=2.6.22.5 --with-headers=/tools/include \ libc_cv_forced_unwind=yes libc_cv_c_cleanup=yes
The meaning of the configure options:

--host=$LFS_TGT, --build=$(../glibc-2.12.1/scripts/config.guess) The combined effect of these switches is that Glibc's build system configures itself to cross-compile, using the cross-linker and cross-compiler in /tools. --disable-profile This builds the libraries without profiling information. Omit this option if profiling on the temporary tools is necessary. --enable-add-ons This tells Glibc to use the NPTL add-on as its threading library. 40

Linux From Scratch - Version 6.7 --enable-kernel=2.6.22.5 This tells Glibc to compile the library with support for 2.6.22.5 and later Linux kernels. Workarounds for older kernels are not enabled. --with-headers=/tools/include This tells Glibc to compile itself against the headers recently installed to the tools directory, so that it knows exactly what features the kernel has and can optimize itself accordingly. libc_cv_forced_unwind=yes The linker installed during Section 5.4, “Binutils-2.20.1 - Pass 1” was cross-compiled and as such cannot be used until Glibc has been installed. This means that the configure test for force-unwind support will fail, as it relies on a working linker. The libc_cv_forced_unwind=yes variable is passed in order to inform configure that force-unwind support is available without it having to run the test. libc_cv_c_cleanup=yes Simlarly, we pass libc_cv_c_cleanup=yes through to the configure script so that the test is skipped and C cleanup handling support is configured. During this stage the following warning might appear: configure: WARNING: *** These auxiliary programs are missing or *** incompatible versions: msgfmt *** some features will be disabled. *** Check the INSTALL file for required versions. The missing or incompatible msgfmt program is generally harmless. This msgfmt program is part of the Gettext package which the host distribution should provide. Compile the package: make This package does come with a test suite, however, it cannot be run at this time because we do not have a C++ compiler yet.

Note
The test suite also requires locale data to be installed in order to run successfully. Locale data provides information to the system regarding such things as the date, time, and currency formats accepted and output by system utilities. If the test suites are not being run in this chapter (as per the recommendation), there is no need to install the locales now. The appropriate locales will be installed in the next chapter. To install the Glibc locales anyway, use instructions from Section 6.9, “Glibc-2.12.1.” Install the package: make install Details on this package are located in Section 6.9.4, “Contents of Glibc.”

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5.8. Adjusting the Toolchain
Now that the temporary C libraries have been installed, all tools compiled in the rest of this chapter should be linked against these libraries. In order to accomplish this, the cross-compiler's specs file needs to be adjusted to point to the new dynamic linker in /tools. This is done by dumping the compiler's “specs” file to a location where it will look for it by default. A simple sed substitution then alters the dynamic linker that GCC will use. The principle here is to find all references to the dynamic linker file in /lib or possibly /lib64 if the host system is 64-bit capable, and adjust them to point to the new location in /tools. For the sake of accuracy, it is recommended to use a copy-and-paste method when issuing the following command. Be sure to visually inspect the specs file to verify that it has properly adjusted all references to the dynamic linker location. Refer to Section 5.2, “Toolchain Technical Notes,” for the default name of the dynamic linker, if necessary. SPECS=`dirname $($LFS_TGT-gcc -print-libgcc-file-name)`/specs $LFS_TGT-gcc -dumpspecs | sed \ -e 's@/lib\(64\)\?/ld@/tools&@g' \ -e "/^\*cpp:$/{n;s,$, -isystem /tools/include,}" > $SPECS echo "New specs file is: $SPECS" unset SPECS

Caution
At this point, it is imperative to stop and ensure that the basic functions (compiling and linking) of the new toolchain are working as expected. To perform a sanity check, run the following commands: echo 'main(){}' > dummy.c $LFS_TGT-gcc -B/tools/lib dummy.c readelf -l a.out | grep ': /tools' If everything is working correctly, there should be no errors, and the output of the last command will be of the form: [Requesting program interpreter: /tools/lib/ld-linux.so.2] Note that /tools/lib, or /tools/lib64 for 64-bit machines appears as the prefix of the dynamic linker. If the output is not shown as above or there was no output at all, then something is wrong. Investigate and retrace the steps to find out where the problem is and correct it. This issue must be resolved before continuing on. Something may have gone wrong with the specs file amendment above. In this case, redo the specs file amendment, being careful to copy-and-paste the commands. Once all is well, clean up the test files: rm -v dummy.c a.out

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Note
Building Binutils in the next section will serve as an additional check that the toolchain has been built properly. If Binutils fails to build, it is an indication that something has gone wrong with the previous Binutils, GCC, or Glibc installations.

CC="$LFS_TGT-gcc -B/tools/lib/" AR=$LFS_TGT-ar RANLIB=$LFS_TGT-ranlib Because this is really a native build of Binutils, setting these variables ensures that the build system uses the cross-compiler and associated tools instead of the ones on the host system. --with-lib-path=/tools/lib This tells the configure script to specify the library search path during the compilation of Binutils, resulting in /tools/lib being passed to the linker. This prevents the linker from searching through library directories on the host. Compile the package: make Install the package: make install Now prepare the linker for the “Re-adjusting” phase in the next chapter: make -C ld clean make -C ld LIB_PATH=/usr/lib:/lib cp -v ld/ld-new /tools/bin
The meaning of the make parameters:

-C ld clean This tells the make program to remove all compiled files in the ld subdirectory. -C ld LIB_PATH=/usr/lib:/lib This option rebuilds everything in the ld subdirectory. Specifying the LIB_PATH Makefile variable on the command line allows us to override the default value of the temporary tools and point it to the proper final path. 44

Linux From Scratch - Version 6.7 The value of this variable specifies the linker's default library search path. This preparation is used in the next chapter. Details on this package are located in Section 6.12.2, “Contents of Binutils.”

5.10.1. Installation of GCC
Versions of GCC later than 4.3 will treat this build as if it were a relocated compiler and disallow searching for startfiles in the location specified by --prefix. Since this will not be a relocated compiler, and the startfiles in /tools are crucial to building a working compiler linked to the libs in /tools, apply the following patch which partially reverts GCC to its old behavior: patch -Np1 -i ../gcc-4.5.1-startfiles_fix-1.patch Under normal circumstances the GCC fixincludes script is run in order to fix potentially broken header files. As GCC-4.5.1 and Glibc-2.12.1 have already been installed at this point, and their respective header files are known to not require fixing, the fixincludes script is not required. In fact, running this script may actually pollute the build environment by installing fixed headers from the host system into GCC's private include directory. The running of the fixincludes script can be suppressed by issuing the following commands: cp -v gcc/Makefile.in{,.orig} sed 's@\./fixinc\.sh@-c true@' gcc/Makefile.in.orig > gcc/Makefile.in For x86 machines, a bootstrap build of GCC uses the -fomit-frame-pointer compiler flag. Non-bootstrap builds omit this flag by default, and the goal should be to produce a compiler that is exactly the same as if it were bootstrapped. Apply the following sed command to force the build to use the flag: cp -v gcc/Makefile.in{,.tmp} sed 's/^T_CFLAGS =$/& -fomit-frame-pointer/' gcc/Makefile.in.tmp \ > gcc/Makefile.in The following command will change the location of GCC's default dynamic linker to use the one installed in /tools. It also removes /usr/include from GCC's include search path. Doing this now rather than adjusting the specs file after installation ensures that the new dynamic linker is used during the actual build of GCC. That is, all of the binaries created during the build will link against the new Glibc. Issue: for file in \ $(find gcc/config -name linux64.h -o -name linux.h -o -name sysv4.h) do cp -uv $file{,.orig} sed -e 's@/lib\(64\)\?\(32\)\?/ld@/tools&@g' \ -e 's@/usr@/tools@g' $file.orig > $file echo ' #undef STANDARD_INCLUDE_DIR #define STANDARD_INCLUDE_DIR 0 #define STANDARD_STARTFILE_PREFIX_1 "" #define STANDARD_STARTFILE_PREFIX_2 ""' >> $file touch $file.orig done 46

Linux From Scratch - Version 6.7 In case the above seems hard to follow, let's break it down a bit. First we find all the files under the gcc/config directory that are named either linux.h, linux64.h or sysv4.h. For each file found, we copy it to a file of the same name but with an added suffix of “.orig”. Then the first sed expression prepends “/tools” to every instance of “/lib/ld”, “/lib64/ld” or “/lib32/ld”, while the second one replaces hard-coded instances of “/usr”. Then we add our define statements which alter the include search path and the default startfile prefix to the end of the file. Finally, we use touch to update the timestamp on the copied files. When used in conjunction with cp -u, this prevents unexpected changes to the original files in case the commands are inadvertently run twice. On x86_64, unsetting the multilib spec for GCC ensures that it won't attempt to link against libraries on the host: case $(uname -m) in x86_64) for file in $(find gcc/config -name t-linux64) ; do \ cp -v $file{,.orig} sed '/MULTILIB_OSDIRNAMES/d' $file.orig > $file done ;; esac As in the first build of GCC it requires the GMP, MPFR and MPC packages. Unpack the tarballs and move them into the required directory names: tar -jxf ../mpfr-3.0.0.tar.bz2 mv -v mpfr-3.0.0 mpfr tar -jxf ../gmp-5.0.1.tar.bz2 mv -v gmp-5.0.1 gmp tar -zxf ../mpc-0.8.2.tar.gz mv -v mpc-0.8.2 mpc Create a separate build directory again: mkdir -v ../gcc-build cd ../gcc-build Before starting to build GCC, remember to unset any environment variables that override the default optimization flags. Now prepare GCC for compilation: CC="$LFS_TGT-gcc -B/tools/lib/" \ AR=$LFS_TGT-ar RANLIB=$LFS_TGT-ranlib \ ../gcc-4.5.1/configure --prefix=/tools \ --with-local-prefix=/tools --enable-clocale=gnu \ --enable-shared --enable-threads=posix \ --enable-__cxa_atexit --enable-languages=c,c++ \ --disable-libstdcxx-pch --disable-multilib \ --disable-bootstrap --disable-libgomp \ --with-gmp-include=$(pwd)/gmp --with-gmp-lib=$(pwd)/gmp/.libs \ --without-ppl --without-cloog 47

Linux From Scratch - Version 6.7
The meaning of the new configure options:

--enable-clocale=gnu This option ensures the correct locale model is selected for the C++ libraries under all circumstances. If the configure script finds the de_DE locale installed, it will select the correct gnu locale model. However, if the de_DE locale is not installed, there is the risk of building Application Binary Interface (ABI)-incompatible C++ libraries because the incorrect generic locale model may be selected. --enable-threads=posix This enables C++ exception handling for multi-threaded code. --enable-__cxa_atexit This option allows use of __cxa_atexit, rather than atexit, to register C++ destructors for local statics and global objects. This option is essential for fully standards-compliant handling of destructors. It also affects the C++ ABI, and therefore results in C++ shared libraries and C++ programs that are interoperable with other Linux distributions. --enable-languages=c,c++ This option ensures that both the C and C++ compilers are built. --disable-libstdcxx-pch Do not build the pre-compiled header (PCH) for libstdc++. It takes up a lot of space, and we have no use for it. --disable-bootstrap For native builds of GCC, the default is to do a "bootstrap" build. This does not just compile GCC, but compiles it several times. It uses the programs compiled in a first round to compile itself a second time, and then again a third time. The second and third iterations are compared to make sure it can reproduce itself flawlessly. This also implies that it was compiled correctly. However, the LFS build method should provide a solid compiler without the need to bootstrap each time. Compile the package: make Install the package: make install As a finishing touch, create a symlink. Many programs and scripts run cc instead of gcc, which is used to keep programs generic and therefore usable on all kinds of UNIX systems where the GNU C compiler is not always installed. Running cc leaves the system administrator free to decide which C compiler to install: ln -vs gcc /tools/bin/cc

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Caution
At this point, it is imperative to stop and ensure that the basic functions (compiling and linking) of the new toolchain are working as expected. To perform a sanity check, run the following commands: echo 'main(){}' > dummy.c cc dummy.c readelf -l a.out | grep ': /tools' If everything is working correctly, there should be no errors, and the output of the last command will be of the form: [Requesting program interpreter: /tools/lib/ld-linux.so.2] Note that /tools/lib, or /tools/lib64 for 64-bit machines appears as the prefix of the dynamic linker. If the output is not shown as above or there was no output at all, then something is wrong. Investigate and retrace the steps to find out where the problem is and correct it. This issue must be resolved before continuing on. First, perform the sanity check again, using gcc instead of cc. If this works, then the /tools/bin/cc symlink is missing. Install the symlink as per above. Next, ensure that the PATH is correct. This can be checked by running echo $PATH and verifying that /tools/bin is at the head of the list. If the PATH is wrong it could mean that you are not logged in as user lfs or that something went wrong back in Section 4.4, “Setting Up the Environment.” Once all is well, clean up the test files: rm -v dummy.c a.out Details on this package are located in Section 6.16.2, “Contents of GCC.”

5.11.1. Installation of Tcl
This package and the next two (Expect and DejaGNU) are installed to support running the test suites for GCC and Binutils. Installing three packages for testing purposes may seem excessive, but it is very reassuring, if not essential, to know that the most important tools are working properly. Even if the test suites are not run in this chapter (they are not mandatory), these packages are required to run the test suites in Chapter 6. Prepare Tcl for compilation: cd unix ./configure --prefix=/tools Build the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Tcl test suite anyway, issue the following command: TZ=UTC make test The Tcl test suite may experience failures under certain host conditions that are not fully understood. Therefore, test suite failures here are not surprising, and are not considered critical. The TZ=UTC parameter sets the time zone to Coordinated Universal Time (UTC), also known as Greenwich Mean Time (GMT), but only for the duration of the test suite run. This ensures that the clock tests are exercised correctly. Details on the TZ environment variable are provided in Chapter 7. Install the package: make install Make the installed library writable so debugging symbols can be removed later: chmod -v u+w /tools/lib/libtcl8.5.so Install Tcl's headers. The next package, Expect, requires them to build. make install-private-headers Now make a necessary symbolic link: ln -sv tclsh8.5 /tools/bin/tclsh

5.12.1. Installation of Expect
First, apply a patch to remove the dependency on Tk, that may be present on the host but will not be available once we enter the chroot environment: patch -Np1 -i ../expect-5.44.1.15-no_tk-1.patch Next, force Expect's configure script to use /bin/stty instead of a /usr/local/bin/stty it may find on the host system. This will ensure that our test suite tools remain sane for the final builds of our toolchain: cp -v configure{,.orig} sed 's:/usr/local/bin:/bin:' configure.orig > configure Now prepare Expect for compilation: ./configure --prefix=/tools --with-tcl=/tools/lib \ --with-tclinclude=/tools/include --with-tk=no
The meaning of the configure options:

--with-tcl=/tools/lib This ensures that the configure script finds the Tcl installation in the temporary tools location instead of possibly locating an existing one on the host system. --with-tclinclude=/tools/include This explicitly tells Expect where to find Tcl's internal headers. Using this option avoids conditions where configure fails because it cannot automatically discover the location of Tcl's headers. --with-tk=no This tells the configure script not to search for Tk (the Tcl GUI component) or the X Window System libraries, both of which may reside on the host system but will not exist in the temporary environment. Build the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Expect test suite anyway, issue the following command: make test Note that the Expect test suite is known to experience failures under certain host conditions that are not within our control. Therefore, test suite failures here are not surprising and are not considered critical. Install the package: make SCRIPTS="" install 52

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The meaning of the make parameter:

SCRIPTS="" This prevents installation of the supplementary Expect scripts, which are not needed.

Short Descriptions
expect Communicates with other interactive programs according to a script libexpect-5.44.a Contains functions that allow Expect to be used as a Tcl extension or to be used directly from C or C++ (without Tcl)

5.13.1. Installation of DejaGNU
The most recent version of this package was released in 2004. Apply some fixes that have accumulated since then: patch -Np1 -i ../dejagnu-1.4.4-consolidated-1.patch Prepare DejaGNU for compilation: ./configure --prefix=/tools Build and install the package: make install To test the results, issue: make check

5.13.2. Contents of DejaGNU
Installed program: runtest

Short Descriptions
runtest A wrapper script that locates the proper expect shell and then runs DejaGNU

--without-ada This ensures that Ncurses does not build support for the Ada compiler which may be present on the host but will not be available once we enter the chroot environment. --enable-overwrite This tells Ncurses to install its header files into /tools/include, instead /tools/include/ncurses, to ensure that other packages can find the Ncurses headers successfully. Compile the package: make This package has a test suite, but it can only be run after the package has been installed. The tests reside in the test/ directory. See the README file in that directory for further details. Install the package: make install Details on this package are located in Section 6.19.2, “Contents of Ncurses.” of

5.15.1. Installation of Bash
Apply a patch that fixes several bugs reported and fixed by the upstream Bash maintainer: patch -Np1 -i ../bash-4.1-fixes-2.patch Prepare Bash for compilation: ./configure --prefix=/tools --without-bash-malloc
The meaning of the configure options:

--without-bash-malloc This option turns off the use of Bash's memory allocation (malloc) function which is known to cause segmentation faults. By turning this option off, Bash will use the malloc functions from Glibc which are more stable. Compile the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Bash test suite anyway, issue the following command: make tests Install the package: make install Make a link for the programs that use sh for a shell: ln -vs bash /tools/bin/sh Details on this package are located in Section 6.29.2, “Contents of Bash.”

5.16.1. Installation of Bzip2
The Bzip2 package does not contain a configure script. Compile and test it with: make Install the package: make PREFIX=/tools install Details on this package are located in Section 6.36.2, “Contents of Bzip2.”

--enable-install-program=hostname This enables the hostname binary to be built and installed – it is disabled by default but is required by the Perl test suite. Compile the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Coreutils test suite anyway, issue the following command: make RUN_EXPENSIVE_TESTS=yes check The RUN_EXPENSIVE_TESTS=yes parameter tells the test suite to run several additional tests that are considered relatively expensive (in terms of CPU power and memory usage) on some platforms, but generally are not a problem on Linux. Install the package: make install The above command refuses to install su because the program cannot be installed setuid root as a non-privileged user. By manually installing it with a different name, we can use it for running tests in the final system as a non-privileged user and we keep a possibly useful su from our host first in our PATH. Install it with: cp -v src/su /tools/bin/su-tools Details on this package are located in Section 6.22.2, “Contents of Coreutils.”

5.18.1. Installation of Diffutils
Prepare Diffutils for compilation: ./configure --prefix=/tools Compile the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Diffutils test suite anyway, issue the following command: make check Install the package: make install Details on this package are located in Section 6.37.2, “Contents of Diffutils.”

5.19.1. Installation of File
Prepare File for compilation: ./configure --prefix=/tools Compile the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the File test suite anyway, issue the following command: make check Install the package: make install Details on this package are located in Section 6.39.2, “Contents of File.”

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5.20. Findutils-4.4.2
The Findutils package contains programs to find files. These programs are provided to recursively search through a directory tree and to create, maintain, and search a database (often faster than the recursive find, but unreliable if the database has not been recently updated). Approximate build time: Required disk space: 0.3 SBU 20 MB

5.20.1. Installation of Findutils
Prepare Findutils for compilation: ./configure --prefix=/tools Compile the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Findutils test suite anyway, issue the following command: make check Install the package: make install Details on this package are located in Section 6.40.2, “Contents of Findutils.”

5.21.1. Installation of Gawk
Prepare Gawk for compilation: ./configure --prefix=/tools Compile the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Gawk test suite anyway, issue the following command: make check Install the package: make install Details on this package are located in Section 6.38.2, “Contents of Gawk.”

5.22.1. Installation of Gettext
For our temporary set of tools, we only need to build and install one binary from Gettext. Prepare Gettext for compilation: cd gettext-tools ./configure --prefix=/tools --disable-shared
The meaning of the configure option:

--disable-shared We do not need to install any of the shared Gettext libraries at this time, therefore there is no need to build them. Compile the package: make -C gnulib-lib make -C src msgfmt As only one binary has been compiled, it is not possible to run the test suite without compiling additional support libraries from the Gettext package. It is therefore not recommended to attempt to run the test suite at this stage. Install the msgfmt binary: cp -v src/msgfmt /tools/bin Details on this package are located in Section 6.42.2, “Contents of Gettext.”

--disable-perl-regexp This ensures that the grep program does not get linked against a Perl Compatible Regular Expression (PCRE) library that may be present on the host but will not be available once we enter the chroot environment. Compile the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Grep test suite anyway, issue the following command: make check Install the package: make install Details on this package are located in Section 6.27.2, “Contents of Grep.”

5.24.1. Installation of Gzip
Prepare Gzip for compilation: ./configure --prefix=/tools Compile the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Gzip test suite anyway, issue the following command: make check Install the package: make install Details on this package are located in Section 6.45.2, “Contents of Gzip.”

5.25.1. Installation of M4
Add a missing include directive that prevents M4 successfully building against Glibc-2.12.1: sed -i -e '/"m4.h"/a\ #include <sys/stat.h>' src/path.c Prepare M4 for compilation: ./configure --prefix=/tools Compile the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the M4 test suite anyway, issue the following command: make check Install the package: make install Details on this package are located in Section 6.24.2, “Contents of M4.”

5.26.1. Installation of Make
Prepare Make for compilation: ./configure --prefix=/tools Compile the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Make test suite anyway, issue the following command: make check Install the package: make install Details on this package are located in Section 6.49.2, “Contents of Make.”

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5.27. Patch-2.6.1
The Patch package contains a program for modifying or creating files by applying a “patch” file typically created by the diff program. Approximate build time: Required disk space: less than 0.1 SBU 1.9 MB

5.27.1. Installation of Patch
Prepare Patch for compilation: ./configure --prefix=/tools Compile the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Patch test suite anyway, issue the following command: make check Install the package: make install Details on this package are located in Section 6.52.2, “Contents of Patch.”

5.28.1. Installation of Perl
First apply the following patch to adapt some hard-wired paths to the C library: patch -Np1 -i ../perl-5.12.1-libc-1.patch Prepare Perl for compilation (make sure to get the 'Data/Dumper Fcntl IO' part of the command correct—they are all letters): sh Configure -des -Dprefix=/tools \ -Dstatic_ext='Data/Dumper Fcntl IO'
The meaning of the configure options:

-Dstatic_ext='Data/Dumper Fcntl IO POSIX' This tells Perl to build the minimum set of static extensions needed for installing and testing the Coreutils and Glibc packages in the next chapter. Only a few of the utilities contained in this package, and one of its libraries, need to be built: make perl utilities ext/Errno/pm_to_blib Although Perl comes with a test suite, it is not recommended to run it at this point. Only part of Perl was built and running make test now will cause the rest of Perl to be built as well, which is unnecessary at this point. The test suite can be run in the next chapter if desired. Install these tools and their libraries: cp -v perl pod/pod2man /tools/bin mkdir -pv /tools/lib/perl5/5.12.1 cp -Rv lib/* /tools/lib/perl5/5.12.1 Details on this package are located in Section 6.33.2, “Contents of Perl.”

5.29.1. Installation of Sed
Prepare Sed for compilation: ./configure --prefix=/tools Compile the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Sed test suite anyway, issue the following command: make check Install the package: make install Details on this package are located in Section 6.17.2, “Contents of Sed.”

5.30.1. Installation of Tar
First fix a bug that was inserted into the latest code release: sed -i /SIGPIPE/d src/tar.c Prepare Tar for compilation: ./configure --prefix=/tools Compile the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Tar test suite anyway, issue the following command: make check Install the package: make install Details on this package are located in Section 6.57.2, “Contents of Tar.”

5.31.1. Installation of Texinfo
Prepare Texinfo for compilation: ./configure --prefix=/tools Compile the package: make Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Texinfo test suite anyway, issue the following command: make check Install the package: make install Details on this package are located in Section 6.58.2, “Contents of Texinfo.”

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5.32. Stripping
The steps in this section are optional, but if the LFS partition is rather small, it is beneficial to learn that unnecessary items can be removed. The executables and libraries built so far contain about 70 MB of unneeded debugging symbols. Remove those symbols with: strip --strip-debug /tools/lib/* strip --strip-unneeded /tools/{,s}bin/* These commands will skip a number of files, reporting that it does not recognize their file format. Most of these are scripts instead of binaries. Take care not to use --strip-unneeded on the libraries. The static ones would be destroyed and the toolchain packages would need to be built all over again. To save nearly 25 MB more, remove the documentation: rm -rf /tools/{,share}/{info,man} At this point, you should have at least 850 MB of free space in $LFS that can be used to build and install Glibc in the next phase. If you can build and install Glibc, you can build and install the rest too.

5.33. Changing Ownership
Note
The commands in the remainder of this book must be performed while logged in as user root and no longer as user lfs. Also, double check that $LFS is set in root's environment. Currently, the $LFS/tools directory is owned by the user lfs, a user that exists only on the host system. If the $LFS/tools directory is kept as is, the files are owned by a user ID without a corresponding account. This is dangerous because a user account created later could get this same user ID and would own the $LFS/tools directory and all the files therein, thus exposing these files to possible malicious manipulation. To avoid this issue, you could add the lfs user to the new LFS system later when creating the /etc/passwd file, taking care to assign it the same user and group IDs as on the host system. Better yet, change the ownership of the $LFS/tools directory to user root by running the following command: chown -R root:root $LFS/tools Although the $LFS/tools directory can be deleted once the LFS system has been finished, it can be retained to build additional LFS systems of the same book version. How best to backup $LFS/tools is a matter of personal preference.

Caution
If you intend to keep the temporary tools for use in building future LFS systems, now is the time to back them up. Subsequent commands in chapter 6 will alter the tools currently in place, rendering them useless for future builds.

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Part III. Building the LFS System

Linux From Scratch - Version 6.7

Chapter 6. Installing Basic System Software
6.1. Introduction
In this chapter, we enter the building site and start constructing the LFS system in earnest. That is, we chroot into the temporary mini Linux system, make a few final preparations, and then begin installing the packages. The installation of this software is straightforward. Although in many cases the installation instructions could be made shorter and more generic, we have opted to provide the full instructions for every package to minimize the possibilities for mistakes. The key to learning what makes a Linux system work is to know what each package is used for and why you (or the system) may need it. We do not recommend using optimizations. They can make a program run slightly faster, but they may also cause compilation difficulties and problems when running the program. If a package refuses to compile when using optimization, try to compile it without optimization and see if that fixes the problem. Even if the package does compile when using optimization, there is the risk it may have been compiled incorrectly because of the complex interactions between the code and build tools. Also note that the -march and -mtune options using values not specified in the book have not been tested. This may cause problems with the toolchain packages (Binutils, GCC and Glibc). The small potential gains achieved in using compiler optimizations are often outweighed by the risks. First-time builders of LFS are encouraged to build without custom optimizations. The subsequent system will still run very fast and be stable at the same time. The order that packages are installed in this chapter needs to be strictly followed to ensure that no program accidentally acquires a path referring to /tools hard-wired into it. For the same reason, do not compile separate packages in parallel. Compiling in parallel may save time (especially on dual-CPU machines), but it could result in a program containing a hard-wired path to /tools, which will cause the program to stop working when that directory is removed. Before the installation instructions, each installation page provides information about the package, including a concise description of what it contains, approximately how long it will take to build, and how much disk space is required during this building process. Following the installation instructions, there is a list of programs and libraries (along with brief descriptions of these) that the package installs.

Note
The SBU values and required disk space includes test suite data for all applicable packages in Chapter 6.

6.2. Preparing Virtual Kernel File Systems
Various file systems exported by the kernel are used to communicate to and from the kernel itself. These file systems are virtual in that no disk space is used for them. The content of the file systems resides in memory. Begin by creating directories onto which the file systems will be mounted: mkdir -v $LFS/{dev,proc,sys}

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6.2.1. Creating Initial Device Nodes
When the kernel boots the system, it requires the presence of a few device nodes, in particular the console and null devices. The device nodes will be created on the hard disk so that they are available before udevd has been started, and additionally when Linux is started with init=/bin/bash. Create the devices by running the following commands: mknod -m 600 $LFS/dev/console c 5 1 mknod -m 666 $LFS/dev/null c 1 3

6.2.2. Mounting and Populating /dev
The recommended method of populating the /dev directory with devices is to mount a virtual filesystem (such as tmpfs) on the /dev directory, and allow the devices to be created dynamically on that virtual filesystem as they are detected or accessed. Device creation is generally done during the boot process by Udev. Since this new system does not yet have Udev and has not yet been booted, it is necessary to mount and populate /dev manually. This is accomplished by bind mounting the host system's /dev directory. A bind mount is a special type of mount that allows you to create a mirror of a directory or mount point to some other location. Use the following command to achieve this: mount -v --bind /dev $LFS/dev

6.3. Package Management
Package Management is an often requested addition to the LFS Book. A Package Manager allows tracking the installation of files making it easy to remove and upgrade packages. As well as the binary and library files, a package manager will handle the installation of configuration files. Before you begin to wonder, NO—this section will not talk about nor recommend any particular package manager. What it provides is a roundup of the more popular techniques and how they work. The perfect package manager for you may be among these techniques or may be a combination of two or more of these techniques. This section briefly mentions issues that may arise when upgrading packages. Some reasons why no package manager is mentioned in LFS or BLFS include: • Dealing with package management takes the focus away from the goals of these books—teaching how a Linux system is built. • There are multiple solutions for package management, each having its strengths and drawbacks. Including one that satisfies all audiences is difficult. There are some hints written on the topic of package management. Visit the Hints Project and see if one of them fits your need. 76

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6.3.1. Upgrade Issues
A Package Manager makes it easy to upgrade to newer versions when they are released. Generally the instructions in the LFS and BLFS Book can be used to upgrade to the newer versions. Here are some points that you should be aware of when upgrading packages, especially on a running system. • If one of the toolchain packages (Glibc, GCC or Binutils) needs to be upgraded to a newer minor version, it is safer to rebuild LFS. Though you may be able to get by rebuilding all the packages in their dependency order, we do not recommend it. For example, if glibc-2.2.x needs to be updated to glibc-2.3.x, it is safer to rebuild. For micro version updates, a simple reinstallation usually works, but is not guaranteed. For example, upgrading from glibc-2.3.4 to glibc-2.3.5 will not usually cause any problems. • If a package containing a shared library is updated, and if the name of the library changes, then all the packages dynamically linked to the library need to be recompiled to link against the newer library. (Note that there is no correlation between the package version and the name of the library.) For example, consider a package foo-1.2.3 that installs a shared library with name libfoo.so.1. Say you upgrade the package to a newer version foo-1.2.4 that installs a shared library with name libfoo.so.2. In this case, all packages that are dynamically linked to libfoo.so.1 need to be recompiled to link against libfoo.so.2. Note that you should not remove the previous libraries until the dependent packages are recompiled.

6.3.2. Package Management Techniques
The following are some common package management techniques. Before making a decision on a package manager, do some research on the various techniques, particularly the drawbacks of the particular scheme.

6.3.2.1. It is All in My Head!
Yes, this is a package management technique. Some folks do not find the need for a package manager because they know the packages intimately and know what files are installed by each package. Some users also do not need any package management because they plan on rebuilding the entire system when a package is changed.

6.3.2.2. Install in Separate Directories
This is a simplistic package management that does not need any extra package to manage the installations. Each package is installed in a separate directory. For example, package foo-1.1 is installed in /usr/pkg/foo-1.1 and a symlink is made from /usr/pkg/foo to /usr/pkg/foo-1.1. When installing a new version foo-1.2, it is installed in /usr/pkg/foo-1.2 and the previous symlink is replaced by a symlink to the new version. Environment variables such as PATH, LD_LIBRARY_PATH, MANPATH, INFOPATH and CPPFLAGS need to be expanded to include /usr/pkg/foo. For more than a few packages, this scheme becomes unmanageable.

6.3.2.3. Symlink Style Package Management
This is a variation of the previous package management technique. Each package is installed similar to the previous scheme. But instead of making the symlink, each file is symlinked into the /usr hierarchy. This removes the need to expand the environment variables. Though the symlinks can be created by the user to automate the creation, many package managers have been written using this approach. A few of the popular ones include Stow, Epkg, Graft, and Depot.

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Linux From Scratch - Version 6.7 The installation needs to be faked, so that the package thinks that it is installed in /usr though in reality it is installed in the /usr/pkg hierarchy. Installing in this manner is not usually a trivial task. For example, consider that you are installing a package libfoo-1.1. The following instructions may not install the package properly: ./configure --prefix=/usr/pkg/libfoo/1.1 make make install The installation will work, but the dependent packages may not link to libfoo as you would expect. If you compile a package that links against libfoo, you may notice that it is linked to /usr/pkg/libfoo/1.1/lib/libfoo. so.1 instead of /usr/lib/libfoo.so.1 as you would expect. The correct approach is to use the DESTDIR strategy to fake installation of the package. This approach works as follows: ./configure --prefix=/usr make make DESTDIR=/usr/pkg/libfoo/1.1 install Most packages support this approach, but there are some which do not. For the non-compliant packages, you may either need to manually install the package, or you may find that it is easier to install some problematic packages into /opt.

6.3.2.4. Timestamp Based
In this technique, a file is timestamped before the installation of the package. After the installation, a simple use of the find command with the appropriate options can generate a log of all the files installed after the timestamp file was created. A package manager written with this approach is install-log. Though this scheme has the advantage of being simple, it has two drawbacks. If, during installation, the files are installed with any timestamp other than the current time, those files will not be tracked by the package manager. Also, this scheme can only be used when one package is installed at a time. The logs are not reliable if two packages are being installed on two different consoles.

6.3.2.5. Tracing Installation Scripts
In this approach, the commands that the installation scripts perform are recorded. There are two techniques that one can use: The LD_PRELOAD environment variable can be set to point to a library to be preloaded before installation. During installation, this library tracks the packages that are being installed by attaching itself to various executables such as cp, install, mv and tracking the system calls that modify the filesystem. For this approach to work, all the executables need to be dynamically linked without the suid or sgid bit. Preloading the library may cause some unwanted side-effects during installation. Therefore, it is advised that one performs some tests to ensure that the package manager does not break anything and logs all the appropriate files. The second technique is to use strace, which logs all system calls made during the execution of the installation scripts.

6.3.2.6. Creating Package Archives
In this scheme, the package installation is faked into a separate tree as described in the Symlink style package management. After the installation, a package archive is created using the installed files. This archive is then used to install the package either on the local machine or can even be used to install the package on other machines. 78

Linux From Scratch - Version 6.7 This approach is used by most of the package managers found in the commercial distributions. Examples of package managers that follow this approach are RPM (which, incidentally, is required by the Linux Standard Base Specification), pkg-utils, Debian's apt, and Gentoo's Portage system. A hint describing how to adopt this style of package management for LFS systems is located at http://www.linuxfromscratch.org/hints/downloads/files/fakeroot. txt. Creation of package files that include dependency information is complex and is beyond the scope of LFS. Slackware uses a tar based system for package archives. This system purposely does not handle package dependencies as more complex package managers do. For details of Slackware package management, see http://www.slackbook. org/html/package-management.html.

6.3.2.7. User Based Management
This scheme, unique to LFS, was devised by Matthias Benkmann, and is available from the Hints Project. In this scheme, each package is installed as a separate user into the standard locations. Files belonging to a package are easily identified by checking the user ID. The features and shortcomings of this approach are too complex to describe in this section. For the details please see the hint at http://www.linuxfromscratch.org/hints/downloads/files/more_control_ and_pkg_man.txt.

6.3.3. Deploying LFS on Multiple Systems
One of the advantages of an LFS system is that there are no files that depend on the position of files on a disk system. Cloning an LFS build to another computer with an architecture similar to the base system is as simple as using tar on the LFS partition that contains the root directory (about 250MB uncompressed for a base LFS build), copying that file via network transfer or CD-ROM to the new system and expanding it. From that point, a few configuration files will have to be changed. Configuration files that may need to be updated include: /etc/hosts, /etc/fstab, /etc/passwd, /etc/group, /etc/shadow, /etc/ld.so.conf, /etc/scsi_ id.config, /etc/sysconfig/network and /etc/sysconfig/network-devices/ifconfig. eth0/ipv4. A custom kernel may need to be built for the new system depending on differences in system hardware and the original kernel configuration. Finally the new system has to be made bootable via Section 8.4, “Using GRUB to Set Up the Boot Process”.

6.4. Entering the Chroot Environment
It is time to enter the chroot environment to begin building and installing the final LFS system. As user root, run the following command to enter the realm that is, at the moment, populated with only the temporary tools: chroot "$LFS" /tools/bin/env -i \ HOME=/root TERM="$TERM" PS1='\u:\w\$ ' \ PATH=/bin:/usr/bin:/sbin:/usr/sbin:/tools/bin \ /tools/bin/bash --login +h The -i option given to the env command will clear all variables of the chroot environment. After that, only the HOME, TERM, PS1, and PATH variables are set again. The TERM=$TERM construct will set the TERM variable inside chroot to the same value as outside chroot. This variable is needed for programs like vim and less to operate properly. If other variables are needed, such as CFLAGS or CXXFLAGS, this is a good place to set them again. From this point on, there is no need to use the LFS variable anymore, because all work will be restricted to the LFS file system. This is because the Bash shell is told that $LFS is now the root (/) directory. 79

Linux From Scratch - Version 6.7 Notice that /tools/bin comes last in the PATH. This means that a temporary tool will no longer be used once its final version is installed. This occurs when the shell does not “remember” the locations of executed binaries—for this reason, hashing is switched off by passing the +h option to bash. Note that the bash prompt will say I have no name! This is normal because the /etc/passwd file has not been created yet.

Note
It is important that all the commands throughout the remainder of this chapter and the following chapters are run from within the chroot environment. If you leave this environment for any reason (rebooting for example), ensure that the virtual kernel filesystems are mounted as explained in Section 6.2.2, “Mounting and Populating /dev” and Section 6.2.3, “Mounting Virtual Kernel File Systems” and enter chroot again before continuing with the installation.

6.5. Creating Directories
It is time to create some structure in the LFS file system. Create a standard directory tree by issuing the following commands: mkdir -pv /{bin,boot,etc/opt,home,lib,mnt,opt} mkdir -pv /{media/{floppy,cdrom},sbin,srv,var} install -dv -m 0750 /root install -dv -m 1777 /tmp /var/tmp mkdir -pv /usr/{,local/}{bin,include,lib,sbin,src} mkdir -pv /usr/{,local/}share/{doc,info,locale,man} mkdir -v /usr/{,local/}share/{misc,terminfo,zoneinfo} mkdir -pv /usr/{,local/}share/man/man{1..8} for dir in /usr /usr/local; do ln -sv share/{man,doc,info} $dir done case $(uname -m) in x86_64) ln -sv lib /lib64 && ln -sv lib /usr/lib64 ;; esac mkdir -v /var/{lock,log,mail,run,spool} mkdir -pv /var/{opt,cache,lib/{misc,locate},local} Directories are, by default, created with permission mode 755, but this is not desirable for all directories. In the commands above, two changes are made—one to the home directory of user root, and another to the directories for temporary files. The first mode change ensures that not just anybody can enter the /root directory—the same as a normal user would do with his or her home directory. The second mode change makes sure that any user can write to the /tmp and /var/tmp directories, but cannot remove another user's files from them. The latter is prohibited by the so-called “sticky bit,” the highest bit (1) in the 1777 bit mask.

6.5.1. FHS Compliance Note
The directory tree is based on the Filesystem Hierarchy Standard (FHS) (available at http://www.pathname.com/fhs/). In addition to the FHS, we create compatibility symlinks for the man, doc, and info directories since many packages still try to install their documentation into /usr/<directory> or /usr/local/<directory> as 80

Linux From Scratch - Version 6.7 opposed to /usr/share/<directory> or /usr/local/share/<directory>. The FHS also stipulates the existence of /usr/local/games and /usr/share/games. The FHS is not precise as to the structure of the /usr/local/share subdirectory, so we create only the directories that are needed. However, feel free to create these directories if you prefer to conform more strictly to the FHS.

6.6. Creating Essential Files and Symlinks
Some programs use hard-wired paths to programs which do not exist yet. In order to satisfy these programs, create a number of symbolic links which will be replaced by real files throughout the course of this chapter after the software has been installed: ln ln ln ln ln -sv -sv -sv -sv -sv /tools/bin/{bash,cat,echo,pwd,stty} /bin /tools/bin/perl /usr/bin /tools/lib/libgcc_s.so{,.1} /usr/lib /tools/lib/libstdc++.so{,.6} /usr/lib bash /bin/sh

A proper Linux system maintains a list of the mounted file systems in the file /etc/mtab. Normally, this file would be created when we mount a new file system. Since we will not be mounting any file systems inside our chroot environment, create an empty file for utilities that expect the presence of /etc/mtab: touch /etc/mtab In order for user root to be able to login and for the name “root” to be recognized, there must be relevant entries in the /etc/passwd and /etc/group files. Create the /etc/passwd file by running the following command: cat > /etc/passwd << "EOF" root:x:0:0:root:/root:/bin/bash bin:x:1:1:bin:/dev/null:/bin/false nobody:x:99:99:Unprivileged User:/dev/null:/bin/false EOF The actual password for root (the “x” used here is just a placeholder) will be set later.

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Linux From Scratch - Version 6.7 Create the /etc/group file by running the following command: cat > /etc/group << "EOF" root:x:0: bin:x:1: sys:x:2: kmem:x:3: tty:x:4: tape:x:5: daemon:x:6: floppy:x:7: disk:x:8: lp:x:9: dialout:x:10: audio:x:11: video:x:12: utmp:x:13: usb:x:14: cdrom:x:15: mail:x:34: nogroup:x:99: EOF The created groups are not part of any standard—they are groups decided on in part by the requirements of the Udev configuration in this chapter, and in part by common convention employed by a number of existing Linux distributions. The Linux Standard Base (LSB, available at http://www.linuxbase.org) recommends only that, besides the group root with a Group ID (GID) of 0, a group bin with a GID of 1 be present. All other group names and GIDs can be chosen freely by the system administrator since well-written programs do not depend on GID numbers, but rather use the group's name. To remove the “I have no name!” prompt, start a new shell. Since a full Glibc was installed in Chapter 5 and the /etc/passwd and /etc/group files have been created, user name and group name resolution will now work: exec /tools/bin/bash --login +h Note the use of the +h directive. This tells bash not to use its internal path hashing. Without this directive, bash would remember the paths to binaries it has executed. To ensure the use of the newly compiled binaries as soon as they are installed, the +h directive will be used for the duration of this chapter. The login, agetty, and init programs (and others) use a number of log files to record information such as who was logged into the system and when. However, these programs will not write to the log files if they do not already exist. Initialize the log files and give them proper permissions: touch /var/run/utmp /var/log/{btmp,lastlog,wtmp} chgrp -v utmp /var/run/utmp /var/log/lastlog chmod -v 664 /var/run/utmp /var/log/lastlog The /var/run/utmp file records the users that are currently logged in. The /var/log/wtmp file records all logins and logouts. The /var/log/lastlog file records when each user last logged in. The /var/log/btmp file records the bad login attempts. 82

6.7.1. Installation of Linux API Headers
The Linux kernel needs to expose an Application Programming Interface (API) for the system's C library (Glibc in LFS) to use. This is done by way of sanitizing various C header files that are shipped in the Linux kernel source tarball. Make sure there are no stale files and dependencies lying around from previous activity: make mrproper Now test and extract the user-visible kernel headers from the source. They are placed in an intermediate local directory and copied to the needed location because the extraction process removes any existing files in the target directory. There are also some hidden files used by the kernel developers and not needed by LFS that are removed from the intermediate directory. make headers_check make INSTALL_HDR_PATH=dest headers_install find dest/include \( -name .install -o -name ..install.cmd \) -delete cp -rv dest/include/* /usr/include

6.9.1. Installation of Glibc
Note
Some packages outside of LFS suggest installing GNU libiconv in order to translate data from one encoding to another. The project's home page (http://www.gnu.org/software/libiconv/) says “This library provides an iconv() implementation, for use on systems which don't have one, or whose implementation cannot convert from/to Unicode.” Glibc provides an iconv() implementation and can convert from/to Unicode, therefore libiconv is not required on an LFS system. The Glibc build system is self-contained and will install perfectly, even though the compiler specs file and linker are still pointing at /tools. The specs and linker cannot be adjusted before the Glibc install because the Glibc autoconf tests would give false results and defeat the goal of achieving a clean build. When running make install, a script called test-installation.pl performs a small sanity test on our newly installed Glibc. However, because our toolchain still points to the /tools directory, the sanity test would be carried out against the wrong Glibc. We can force the script to check the Glibc we have just installed with the following: DL=$(readelf -l /bin/sh | sed -n 's@.*interpret.*/tools\(.*\)]$@\1@p') sed -i "s|libs -o|libs -L/usr/lib -Wl,-dynamic-linker=$DL -o|" \ scripts/test-installation.pl unset DL The ldd shell script contains Bash-specific syntax. Change its default program interpreter to /bin/bash in case another /bin/sh is installed as described in the Shells chapter of the BLFS book: sed -i 's|@BASH@|/bin/bash|' elf/ldd.bash.in Fix a bug that prevents Glibc from building with GCC-4.5.1: patch -Np1 -i ../glibc-2.12.1-gcc_fix-1.patch Fix a bug that prevents Glibc from building with versions of Make newer than 3.81. patch -Np1 -i ../glibc-2.12.1-makefile_fix-1.patch The Glibc documentation recommends building Glibc outside of the source directory in a dedicated build directory: mkdir -v ../glibc-build cd ../glibc-build 85

--libexecdir=/usr/lib/glibc This changes the location of the pt_chown program from its default of /usr/libexec to /usr/lib/glibc. Compile the package: make

Important
In this section, the test suite for Glibc is considered critical. Do not skip it under any circumstance. Before running the tests, copy a file from the source tree into our build tree to prevent a couple of test failures, then test the results: cp -v ../glibc-2.12.1/iconvdata/gconv-modules iconvdata make -k check 2>&1 | tee glibc-check-log grep Error glibc-check-log You will probably see an expected (ignored) failure in the posix/annexc test. In addition the Glibc test suite is somewhat dependent on the host system. This is a list of the most common issues: • The nptl/tst-clock2, nptl/tst-attr3, and rt/tst-cpuclock2 tests have been known to fail. The reason is not completely understood, but indications are that minor timing issues can trigger these failures. • The math tests sometimes fail when running on systems where the CPU is not a relatively new genuine Intel or authentic AMD processor. • If you have mounted the LFS partition with the noatime option, the atime test will fail. As mentioned in Section 2.4, “Mounting the New Partition”, do not use the noatime option while building LFS. • When running on older and slower hardware or on systems under load, some tests can fail because of test timeouts being exceeded. Modifying the make check command to set a TIMEOUTFACTOR is reported to help eliminate these errors (e.g. TIMEOUTFACTOR=16 make -k check). Though it is a harmless message, the install stage of Glibc will complain about the absence of /etc/ld.so.conf. Prevent this warning with: touch /etc/ld.so.conf 86

In addition, install the locale for your own country, language and character set. Alternatively, install all locales listed in the glibc-2.12.1/localedata/SUPPORTED file (it includes every locale listed above and many more) at once with the following time-consuming command: make localedata/install-locales Then use the localedef command to create and install locales not listed in the glibc-2.12. 1/localedata/SUPPORTED file in the unlikely case you need them.

6.9.2. Configuring Glibc
The /etc/nsswitch.conf file needs to be created because, although Glibc provides defaults when this file is missing or corrupt, the Glibc defaults do not work well in a networked environment. The time zone also needs to be configured.

87

Linux From Scratch - Version 6.7 Create a new file /etc/nsswitch.conf by running the following: cat > /etc/nsswitch.conf << "EOF" # Begin /etc/nsswitch.conf passwd: files group: files shadow: files hosts: files dns networks: files protocols: files services: files ethers: files rpc: files # End /etc/nsswitch.conf EOF One way to determine the local time zone, run the following script: tzselect After answering a few questions about the location, the script will output the name of the time zone (e.g., America/Edmonton). There are also some other possible timezones listed in /usr/share/zoneinfo such as Canada/Eastern or EST5EDT that are not identified by the script but can be used. Then create the /etc/localtime file by running: cp -v --remove-destination /usr/share/zoneinfo/<xxx> \ /etc/localtime Replace <xxx> with the name of the time zone selected (e.g., Canada/Eastern).
The meaning of the cp option:

--remove-destination This is needed to force removal of the already existing symbolic link. The reason for copying the file instead of using a symlink is to cover the situation where /usr is on a separate partition. This could be important when booted into single user mode.

6.9.3. Configuring the Dynamic Loader
By default, the dynamic loader (/lib/ld-linux.so.2) searches through /lib and /usr/lib for dynamic libraries that are needed by programs as they are run. However, if there are libraries in directories other than /lib and /usr/lib, these need to be added to the /etc/ld.so.conf file in order for the dynamic loader to find them. Two directories that are commonly known to contain additional libraries are /usr/local/lib and /opt/lib, so add those directories to the dynamic loader's search path. 88

Short Descriptions
catchsegv gencat getconf getent iconv iconvconfig ldconfig ldd lddlibc4 locale localedef mtrace nscd pcprofiledump Can be used to create a stack trace when a program terminates with a segmentation fault Generates message catalogues Displays the system configuration values for file system specific variables Gets entries from an administrative database Performs character set conversion Creates fastloading iconv module configuration files Configures the dynamic linker runtime bindings Reports which shared libraries are required by each given program or shared library Assists ldd with object files Prints various information about the current locale Compiles locale specifications Reads and interprets a memory trace file and displays a summary in human-readable format A daemon that provides a cache for the most common name service requests Dumps information generated by PC profiling 89

Linux From Scratch - Version 6.7 pt_chown rpcgen rpcinfo sln sprof tzselect xtrace zdump zic ld.so A helper program for grantpt to set the owner, group and access permissions of a slave pseudo terminal Generates C code to implement the Remote Procedure Call (RPC) protocol Makes an RPC call to an RPC server A statically linked ln program Reads and displays shared object profiling data Asks the user about the location of the system and reports the corresponding time zone description Traces the execution of a program by printing the currently executed function The time zone dumper The time zone compiler The helper program for shared library executables

libBrokenLocale Used internally by Glibc as a gross hack to get broken programs (e.g., some Motif applications) running. See comments in glibc-2.12.1/locale/broken_cur_ max.c for more information libSegFault libanl libbsd-compat libc libcidn libcrypt libdl libg libieee The segmentation fault signal handler, used by catchsegv An asynchronous name lookup library Provides the portability needed in order to run certain Berkeley Software Distribution (BSD) programs under Linux The main C library Used internally by Glibc for handling internationalized domain names in the getaddrinfo() function The cryptography library The dynamic linking interface library Dummy library containing no functions. Previously was a runtime library for g++ Linking in this module forces error handling rules for math functions as defined by the Institute of Electrical and Electronic Engineers (IEEE). The default is POSIX.1 error handling The mathematical library Turns on memory allocation checking when linked to Used by memusage to help collect information about the memory usage of a program The network services library The Name Service Switch libraries, containing functions for resolving host names, user names, group names, aliases, services, protocols, etc. Contains profiling functions used to track the amount of CPU time spent in specific source code lines The POSIX threads library Contains functions for creating, sending, and interpreting packets to the Internet domain name servers 90

Linux From Scratch - Version 6.7 librpcsvc librt libthread_db libutil Contains functions providing miscellaneous RPC services Contains functions providing most of the interfaces specified by the POSIX.1b Realtime Extension Contains functions useful for building debuggers for multi-threaded programs Contains code for “standard” functions used in many different Unix utilities

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6.10. Re-adjusting the Toolchain
Now that the final C libraries have been installed, it is time to adjust the toolchain again. The toolchain will be adjusted so that it will link any newly compiled program against these new libraries. This is a similar process used in the “Adjusting” phase in the beginning of Chapter 5, but with the adjustments reversed. In Chapter 5, the chain was guided from the host's /{,usr/}lib directories to the new /tools/lib directory. Now, the chain will be guided from that same /tools/lib directory to the LFS /{,usr/}lib directories. First, backup the /tools linker, and replace it with the adjusted linker we made in chapter 5. We'll also create a link to its counterpart in /tools/$(gcc -dumpmachine)/bin: mv mv mv ln -v /tools/bin/{ld,ld-old} -v /tools/$(gcc -dumpmachine)/bin/{ld,ld-old} -v /tools/bin/{ld-new,ld} -sv /tools/bin/ld /tools/$(gcc -dumpmachine)/bin/ld

Next, amend the GCC specs file so that it points to the new dynamic linker. Simply deleting all instances of “/tools” should leave us with the correct path to the dynamic linker. Also adjust the specs file so that GCC knows where to find the correct headers and Glibc start files. A sed command accomplishes this: gcc -dumpspecs | sed -e 's@/tools@@g' \ -e '/\*startfile_prefix_spec:/{n;s@.*@/usr/lib/ @}' \ -e '/\*cpp:/{n;s@$@ -isystem /usr/include@}' > \ `dirname $(gcc --print-libgcc-file-name)`/specs It is a good idea to visually inspect the specs file to verify the intended change was actually made. It is imperative at this point to ensure that the basic functions (compiling and linking) of the adjusted toolchain are working as expected. To do this, perform the following sanity checks: echo 'main(){}' > dummy.c cc dummy.c -v -Wl,--verbose &> dummy.log readelf -l a.out | grep ': /lib' If everything is working correctly, there should be no errors, and the output of the last command will be (allowing for platform-specific differences in dynamic linker name): [Requesting program interpreter: /lib/ld-linux.so.2] Note that /lib is now the prefix of our dynamic linker. Now make sure that we're setup to use the correct startfiles: grep -o '/usr/lib.*/crt[1in].*succeeded' dummy.log If everything is working correctly, there should be no errors, and the output of the last command will be: /usr/lib/crt1.o succeeded /usr/lib/crti.o succeeded /usr/lib/crtn.o succeeded Verify that the compiler is searching for the correct header files: grep -B1 '^ /usr/include' dummy.log 92

Linux From Scratch - Version 6.7 This command should return successfully with the following output: #include <...> search starts here: /usr/include Next, verify that the new linker is being used with the correct search paths: grep 'SEARCH.*/usr/lib' dummy.log |sed 's|; |\n|g' If everything is working correctly, there should be no errors, and the output of the last command (allowing for platform-specific target triplets) will be: SEARCH_DIR("/tools/i686-pc-linux-gnu/lib") SEARCH_DIR("/usr/lib") SEARCH_DIR("/lib"); Next make sure that we're using the correct libc: grep "/lib.*/libc.so.6 " dummy.log If everything is working correctly, there should be no errors, and the output of the last command (allowing for a lib64 directory on 64-bit hosts) will be: attempt to open /lib/libc.so.6 succeeded Lastly, make sure GCC is using the correct dynamic linker: grep found dummy.log If everything is working correctly, there should be no errors, and the output of the last command will be (allowing for platform-specific differences in dynamic linker name and a lib64 directory on 64-bit hosts): found ld-linux.so.2 at /lib/ld-linux.so.2 If the output does not appear as shown above or is not received at all, then something is seriously wrong. Investigate and retrace the steps to find out where the problem is and correct it. The most likely reason is that something went wrong with the specs file adjustment. Any issues will need to be resolved before continuing on with the process. Once everything is working correctly, clean up the test files: rm -v dummy.c a.out dummy.log

CFLAGS='-mstackrealign -fPIC -O3' Setting CFLAGS overrides the default optimization in the package to prevent some run time errors. Note that the -mstackrealign may cause build failures in non-Intel architeture systems. Compile the package: make To test the results, issue: make check Install the package: make install The shared library needs to be moved to /lib, and as a result the .so file in /usr/lib will need to be recreated: mv -v /usr/lib/libz.so.* /lib ln -sfv ../../lib/libz.so.1.2.5 /usr/lib/libz.so

6.11.2. Contents of Zlib
Installed libraries: libz.{a,so}

Short Descriptions
libz Contains compression and decompression functions used by some programs

6.12.1. Installation of Binutils
Verify that the PTYs are working properly inside the chroot environment by performing a simple test: expect -c "spawn ls" This command should output the following: spawn ls If, instead, the output includes the message below, then the environment is not set up for proper PTY operation. This issue needs to be resolved before running the test suites for Binutils and GCC: The system has no more ptys. Ask your system administrator to create more. Suppress the installation of an outdated standards.info file as a newer one is installed later on in the Autoconf instructions: rm -fv etc/standards.info sed -i.bak '/^INFO/s/standards.info //' etc/Makefile.in The Binutils documentation recommends building Binutils outside of the source directory in a dedicated build directory: mkdir -v ../binutils-build cd ../binutils-build Prepare Binutils for compilation: ../binutils-2.20.1/configure --prefix=/usr \ --enable-shared Compile the package: make tooldir=/usr
The meaning of the make parameter:

tooldir=/usr Normally, the tooldir (the directory where the executables will ultimately be located) is set to $(exec_ prefix)/$(target_alias). For example, x86_64 machines would expand that to /usr/x86_ 64-unknown-linux-gnu. Because this is a custom system, this target-specific directory in /usr is not required. $(exec_prefix)/$(target_alias) would be used if the system was used to cross-compile (for example, compiling a package on an Intel machine that generates code that can be executed on PowerPC machines). 95

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Important
The test suite for Binutils in this section is considered critical. Do not skip it under any circumstances. Test the results: make check Install the package: make tooldir=/usr install Install the libiberty header file that is needed by some packages: cp -v ../binutils-2.20.1/include/libiberty.h /usr/include

Short Descriptions
addr2line Translates program addresses to file names and line numbers; given an address and the name of an executable, it uses the debugging information in the executable to determine which source file and line number are associated with the address Creates, modifies, and extracts from archives An assembler that assembles the output of gcc into object files Used by the linker to de-mangle C++ and Java symbols and to keep overloaded functions from clashing Displays call graph profile data A linker that combines a number of object and archive files into a single file, relocating their data and tying up symbol references Lists the symbols occurring in a given object file Translates one type of object file into another Displays information about the given object file, with options controlling the particular information to display; the information shown is useful to programmers who are working on the compilation tools Generates an index of the contents of an archive and stores it in the archive; the index lists all of the symbols defined by archive members that are relocatable object files Displays information about ELF type binaries Lists the section sizes and the total size for the given object files Outputs, for each given file, the sequences of printable characters that are of at least the specified length (defaulting to four); for object files, it prints, by default, only the strings from the initializing and loading sections while for other types of files, it scans the entire file 96

6.13.1. Installation of GMP
Note
If you are building for 32-bit x86, but you have a CPU which is capable of running 64-bit code and you have specified CFLAGS in the environment, the configure script will attempt to configure for 64-bits and fail. Avoid this by invoking the configure command below with ABI=32 ./configure ... Prepare GMP for compilation: ./configure --prefix=/usr --enable-cxx --enable-mpbsd
The meaning of the new configure options:

--enable-cxx This parameter enables C++ support --enable-mpbsd This builds the Berkeley MP compatibility library Compile the package: make

Important
The test suite for GMP in this section is considered critical. Do not skip it under any circumstances. Test the results: make check 2>&1 | tee gmp-check-log Ensure that all 162 tests in the test suite passed. Check the results by issuing the following command: awk '/tests passed/{total+=$2} ; END{print total}' gmp-check-log Install the package: make install If desired, install the documentation: mkdir -v /usr/share/doc/gmp-5.0.1 cp -v doc/{isa_abi_headache,configuration} doc/*.html \ /usr/share/doc/gmp-5.0.1 98

Important
The test suite for MPFR in this section is considered critical. Do not skip it under any circumstances. Test the results and ensure that all tests passed: make check Install the package: make install Install the documentation: make html make install-html

6.16.1. Installation of GCC
Apply a sed substitution that will suppress the installation of libiberty.a. The version of libiberty.a provided by Binutils will be used instead: sed -i 's/install_to_$(INSTALL_DEST) //' libiberty/Makefile.in As in Section 5.10, “GCC-4.5.1 - Pass 2”, apply the following sed to force the build to use the -fomit-frame-pointer compiler flag in order to ensure consistent compiler builds: case `uname -m` in i?86) sed -i 's/^T_CFLAGS =$/& -fomit-frame-pointer/' \ gcc/Makefile.in ;; esac The fixincludes script is known to occasionally erroneously attempt to "fix" the system headers installed so far. As the headers up to this point are known to not require fixing, issue the following command to prevent the fixincludes script from running: sed -i 's@\./fixinc\.sh@-c true@' gcc/Makefile.in The GCC documentation recommends building GCC outside of the source directory in a dedicated build directory: mkdir -v ../gcc-build cd ../gcc-build Prepare GCC for compilation: ../gcc-4.5.1/configure --prefix=/usr \ --libexecdir=/usr/lib --enable-shared \ --enable-threads=posix --enable-__cxa_atexit \ --enable-clocale=gnu --enable-languages=c,c++ \ --disable-multilib --disable-bootstrap --with-system-zlib Note that for other languages, there are some prerequisites that are not available. See the BLFS Book for instructions on how to build all the GCC supported languages.
The meaning of the new configure option:

--with-system-zlib This switch tells GCC to link to the system installed copy of the Zlib library, rather than its own internl copy. Compile the package: make 102

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Important
In this section, the test suite for GCC is considered critical. Do not skip it under any circumstance. One set of tests in the GCC test suite is known to exhaust the stack, so increase the stack size prior to running the tests: ulimit -s 16384 Test the results, but do not stop at errors: make -k check To receive a summary of the test suite results, run: ../gcc-4.5.1/contrib/test_summary For only the summaries, pipe the output through grep -A7 Summ. Results can be compared with those located at http://www.linuxfromscratch.org/lfs/build-logs/6.7/ and http://gcc.gnu. org/ml/gcc-testresults/. A few unexpected failures cannot always be avoided. The GCC developers are usually aware of these issues, but have not resolved them yet. In particular, the libmudflap tests are known be particularly problematic as a result of a bug in GCC (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20003). Unless the test results are vastly different from those at the above URL, it is safe to continue. Install the package: make install Some packages expect the C preprocessor to be installed in the /lib directory. To support those packages, create this symlink: ln -sv ../usr/bin/cpp /lib Many packages use the name cc to call the C compiler. To satisfy those packages, create a symlink: ln -sv gcc /usr/bin/cc Now that our final toolchain is in place, it is important to again ensure that compiling and linking will work as expected. We do this by performing the same sanity checks as we did earlier in the chapter: echo 'main(){}' > dummy.c cc dummy.c -v -Wl,--verbose &> dummy.log readelf -l a.out | grep ': /lib' If everything is working correctly, there should be no errors, and the output of the last command will be (allowing for platform-specific differences in dynamic linker name): [Requesting program interpreter: /lib/ld-linux.so.2] Now make sure that we're setup to use the correct startfiles: grep -o '/usr/lib.*/crt[1in].*succeeded' dummy.log 103

Linux From Scratch - Version 6.7 If everything is working correctly, there should be no errors, and the output of the last command will be: /usr/lib/gcc/i686-pc-linux-gnu/4.5.1/../../../crt1.o succeeded /usr/lib/gcc/i686-pc-linux-gnu/4.5.1/../../../crti.o succeeded /usr/lib/gcc/i686-pc-linux-gnu/4.5.1/../../../crtn.o succeeded Depending on your machine architecture, the above may differ slightly, the difference usually being the name of the directory after /usr/lib/gcc. If your machine is a 64-bit system, you may also see a directory named lib64 towards the end of the string. The important thing to look for here is that gcc has found all three crt*.o files under the /usr/lib directory. Verify that the compiler is searching for the correct header files: grep -B4 '^ /usr/include' dummy.log This command should return successfully with the following output: #include <...> search starts here: /usr/local/include /usr/lib/gcc/i686-pc-linux-gnu/4.5.1/include /usr/lib/gcc/i686-pc-linux-gnu/4.5.1/include-fixed /usr/include Again, note that the directory named after your target triplet may be different than the above, depending on your architecture.

Note
As of version 4.3.0, GCC now unconditionally installs the limits.h file into the private include-fixed directory, and that directory is required to be in place. Next, verify that the new linker is being used with the correct search paths: grep 'SEARCH.*/usr/lib' dummy.log |sed 's|; |\n|g' If everything is working correctly, there should be no errors, and the output of the last command (allowing for platform-specific target triplets) will be: SEARCH_DIR("/usr/i686-pc-linux-gnu/lib") SEARCH_DIR("/usr/local/lib") SEARCH_DIR("/lib") SEARCH_DIR("/usr/lib"); A 64-bit system may see a few more directories. For example, here is the output from an x86_64 machine: SEARCH_DIR("/usr/x86_64-unknown-linux-gnu/lib64") SEARCH_DIR("/usr/local/lib64") SEARCH_DIR("/lib64") SEARCH_DIR("/usr/lib64") SEARCH_DIR("/usr/x86_64-unknown-linux-gnu/lib") SEARCH_DIR("/usr/local/lib") SEARCH_DIR("/lib") SEARCH_DIR("/usr/lib"); 104

Linux From Scratch - Version 6.7 Next make sure that we're using the correct libc: grep "/lib.*/libc.so.6 " dummy.log If everything is working correctly, there should be no errors, and the output of the last command (allowing for a lib64 directory on 64-bit hosts) will be: attempt to open /lib/libc.so.6 succeeded Lastly, make sure GCC is using the correct dynamic linker: grep found dummy.log If everything is working correctly, there should be no errors, and the output of the last command will be (allowing for platform-specific differences in dynamic linker name and a lib64 directory on 64-bit hosts): found ld-linux.so.2 at /lib/ld-linux.so.2 If the output does not appear as shown above or is not received at all, then something is seriously wrong. Investigate and retrace the steps to find out where the problem is and correct it. The most likely reason is that something went wrong with the specs file adjustment. Any issues will need to be resolved before continuing on with the process. Once everything is working correctly, clean up the test files: rm -v dummy.c a.out dummy.log

Short Descriptions
c++ cc cpp g++ gcc gccbug gcov libgcc libgcov libgomp The C++ compiler The C compiler The C preprocessor; it is used by the compiler to expand the #include, #define, and similar statements in the source files The C++ compiler The C compiler A shell script used to help create useful bug reports A coverage testing tool; it is used to analyze programs to determine where optimizations will have the most effect Contains run-time support for gcc This library is linked in to a program when GCC is instructed to enable profiling GNU implementation of the OpenMP API for multi-platform shared-memory parallel programming in C/C++ and Fortran 105

6.17.1. Installation of Sed
Prepare Sed for compilation: ./configure --prefix=/usr --bindir=/bin --htmldir=/usr/share/doc/sed-4.2.1
The meaning of the new configure option:

--htmldir This sets the directory where the HTML documentation will be installed to. Compile the package: make Generate the HTML documentation: make html To test the results, issue: make check Install the package: make install Install the HTML documentation: make -C doc install-html

6.18.1. Installation of Pkg-config
First fix a problem with underquoting that shows up in later versions of autoconf: sed -i -e 's/XT])dnl/XT])[]dnl/' \ -e 's/\.])dnl/\.])[]dnl/' pkg.m4 Prepare Pkg-config for compilation: ./configure --prefix=/usr Compile the package: make To test the results, issue: make check Install the package: make install

6.18.2. Contents of Pkg-config
Installed program: pkg-config

Short Descriptions
pkg-config Returns meta information for the specified library or package.

--enable-widec This switch causes wide-character libraries (e.g., libncursesw.so.5.7) to be built instead of normal ones (e.g., libncurses.so.5.7). These wide-character libraries are usable in both multibyte and traditional 8-bit locales, while normal libraries work properly only in 8-bit locales. Wide-character and normal libraries are source-compatible, but not binary-compatible. Compile the package: make This package has a test suite, but it can only be run after the package has been installed. The tests reside in the test/ directory. See the README file in that directory for further details. Install the package: make install Move the shared libraries to the /lib directory, where they are expected to reside: mv -v /usr/lib/libncursesw.so.5* /lib Because the libraries have been moved, one symlink points to a non-existent file. Recreate it: ln -sfv ../../lib/libncursesw.so.5 /usr/lib/libncursesw.so Many applications still expect the linker to be able to find non-wide-character Ncurses libraries. Trick such applications into linking with wide-character libraries by means of symlinks and linker scripts: for lib in ncurses form panel menu ; do \ rm -vf /usr/lib/lib${lib}.so ; \ echo "INPUT(-l${lib}w)" >/usr/lib/lib${lib}.so ; \ ln -sfv lib${lib}w.a /usr/lib/lib${lib}.a ; \ done ln -sfv libncurses++w.a /usr/lib/libncurses++.a Finally, make sure that old applications that look for -lcurses at build time are still buildable: rm -vf /usr/lib/libcursesw.so echo "INPUT(-lncursesw)" >/usr/lib/libcursesw.so ln -sfv libncurses.so /usr/lib/libcurses.so ln -sfv libncursesw.a /usr/lib/libcursesw.a ln -sfv libncurses.a /usr/lib/libcurses.a 109

Note
The instructions above don't create non-wide-character Ncurses libraries since no package installed by compiling from sources would link against them at runtime. If you must have such libraries because of some binary-only application or to be compliant with LSB, build the package again with the following commands: make distclean ./configure --prefix=/usr --with-shared --without-normal \ --without-debug --without-cxx-binding make sources libs cp -av lib/lib*.so.5* /usr/lib

Short Descriptions
captoinfo clear infocmp infotocap ncursesw5-config reset tic Converts a termcap description into a terminfo description Clears the screen, if possible Compares or prints out terminfo descriptions Converts a terminfo description into a termcap description Provides configuration information for ncurses Reinitializes a terminal to its default values The terminfo entry-description compiler that translates a terminfo file from source format into the binary format needed for the ncurses library routines. A terminfo file contains information on the capabilities of a certain terminal Lists all available terminal types, giving the primary name and description for each Makes the values of terminal-dependent capabilities available to the shell; it can also be used to reset or initialize a terminal or report its long name Can be used to initialize terminals A link to libncurses Contains functions to display text in many complex ways on a terminal screen; a good example of the use of these functions is the menu displayed during the kernel's make menuconfig 110

6.20.1. FHS compliance notes
The FHS recommends using the /var/lib/hwclock directory instead of the usual /etc directory as the location for the adjtime file. To make the hwclock program FHS-compliant, run the following: sed -e 's@etc/adjtime@var/lib/hwclock/adjtime@g' \ -i $(grep -rl '/etc/adjtime' .) mkdir -pv /var/lib/hwclock

--enable-arch Enables building the arch program --enable-partx Enables building the addpart, delpart and partx programs --enable-write Enables building the write program Compile the package: make This package does not come with a test suite. Install the package: make install

Short Descriptions
addpart agetty arch blkid blockdev cal cfdisk chkdupexe chrt col colcrt colrm column ctrlaltdel cytune ddate delpart dmesg fallocate fdformat fdisk findfs findmnt flock fsck fsck.cramfs fsck.minix fsfreeze getopt hexdump hwclock i386 ionice ipcmk Informs the Linux kernel of new partitions Opens a tty port, prompts for a login name, and then invokes the login program Reports the machine's architecture A command line utility to locate and print block device attributes Allows users to call block device ioctls from the command line Displays a simple calendar Manipulates the partition table of the given device Finds duplicate executables Manipulates real-time attributes of a process Filters out reverse line feeds Filters nroff output for terminals that lack some capabilities, such as overstriking and half-lines Filters out the given columns Formats a given file into multiple columns Sets the function of the Ctrl+Alt+Del key combination to a hard or a soft reset Tunes the parameters of the serial line drivers for Cyclades cards Gives the Discordian date or converts the given Gregorian date to a Discordian one Asks the Linux kernel to remove a partition Dumps the kernel boot messages Preallocates space to a file Low-level formats a floppy disk Manipulates the paritition table of the given device Finds a file system by label or Universally Unique Identifier (UUID) Is a command line interface to the libmount library for work with mountinfo, fstab and mtab files Acquires a file lock and then executes a command with the lock held Is used to check, and optionally repair, file systems Performs a consistency check on the Cramfs file system on the given device Performs a consistency check on the Minix file system on the given device Is a very simple wrapper around FIFREEZE/FITHAW ioctl kernel driver operations Parses options in the given command line Dumps the given file in hexadecimal or in another given format Reads or sets the system's hardware clock, also called the Real-Time Clock (RTC) or Basic Input-Output System (BIOS) clock A symbolic link to setarch Gets or sets the io scheduling class and priority for a program Creates various IPC resources 113

Linux From Scratch - Version 6.7 ipcrm ipcs isosize ldattach line linux32 linux64 logger look losetup lscpu mcookie mkfs mkfs.bfs mkfs.cramfs mkfs.minix mkswap more mount namei partx pg pivot_root readprofile rename renice rev rtcwake script scriptreplay setarch setsid setterm sfdisk swaplabel swapoff Removes the given Inter-Process Communication (IPC) resource Provides IPC status information Reports the size of an iso9660 file system Attaches a line discipline to a serial line Copies a single line A symbolic link to setarch A symbolic link to setarch Enters the given message into the system log Displays lines that begin with the given string Sets up and controls loop devices Prints CPU architechture information Generates magic cookies (128-bit random hexadecimal numbers) for xauth Builds a file system on a device (usually a hard disk partition) Creates a Santa Cruz Operations (SCO) bfs file system Creates a cramfs file system Creates a Minix file system Initializes the given device or file to be used as a swap area A filter for paging through text one screen at a time Attaches the file system on the given device to a specified directory in the file-system tree Shows the symbolic links in the given pathnames Tells the kernel about the presence and numbering of on-disk partitions Displays a text file one screen full at a time Makes the given file system the new root file system of the current process Reads kernel profiling information Renames the given files, replacing a given string with another Alters the priority of running processes Reverses the lines of a given file Used to enter a system sleep state until specified wakeup time Makes a typescript of a terminal session Plays back typescripts using timing information Changes reported architecture in a new program environment and sets personality flags Runs the given program in a new session Sets terminal attributes A disk partition table manipulator Allows to change swaparea UUID and label Disables devices and files for paging and swapping 114

Linux From Scratch - Version 6.7 swapon switch_root tailf taskset tunelp ul umount unshare uuidd uuidgen wall whereis wipefs write libblkid libuuid Enables devices and files for paging and swapping and lists the devices and files currently in use Switches to another filesystem as the root of the mount tree Tracks the growth of a log file. Displays the last 10 lines of a log file, then continues displaying any new entries in the log file as they are created Retrieves or sets a process' CPU affinity Tunes the parameters of the line printer A filter for translating underscores into escape sequences indicating underlining for the terminal in use Disconnects a file system from the system's file tree Runs a program with some namespaces unshared from parent A daemon used by the UUID library to generate time-based UUIDs in a secure and guranteed-unique fashion. Creates new UUIDs. Each new UUID can reasonably be considered unique among all UUIDs created, on the local system and on other systems, in the past and in the future Displays the contents of a file or, by default, its standard input, on the terminals of all currently logged in users Reports the location of the binary, source, and man page for the given command Wipes a filesystem signature from a device Sends a message to the given user if that user has not disabled receipt of such messages Contains routines for device identification and token extraction Contains routines for generating unique identifiers for objects that may be accessible beyond the local system

6.21.1. Installation of E2fsprogs
The E2fsprogs documentation recommends that the package be built in a subdirectory of the source tree: mkdir -v build cd build Prepare E2fsprogs for compilation: ../configure --prefix=/usr --with-root-prefix="" \ --enable-elf-shlibs --disable-libblkid --disable-libuuid \ --disable-uuidd --disable-fsck
The meaning of the configure options:

--with-root-prefix="" Certain programs (such as the e2fsck program) are considered essential programs. When, for example, /usr is not mounted, these programs still need to be available. They belong in directories like /lib and /sbin. If this option is not passed to E2fsprogs' configure, the programs are installed into the /usr directory. --enable-elf-shlibs This creates the shared libraries which some programs in this package use. --disable-* This prevents E2fsprogs from building and installing the libuuid and libblkid libraries, the uuidd daemon, and the fsck wrapper, as Util-Linux-NG installed all of them earlier. Compile the package: make To test the results, issue: make check One of the E2fsprogs tests will attempt to allocate 256 MB of memory. If you do not have significantly more RAM than this, it is recommended to enable sufficient swap space for the test. See Section 2.3, “Creating a File System on the Partition” and Section 2.4, “Mounting the New Partition” for details on creating and enabling swap space. Install the binaries, documentation, and shared libraries: make install Install the static libraries and headers: make install-libs 116

Short Descriptions
badblocks chattr compile_et debugfs dumpe2fs e2freefrag e2fsck e2image e2initrd_helper e2label e2undo filefrag Searches a device (usually a disk partition) for bad blocks Changes the attributes of files on an ext2 file system; it also changes ext3 file systems, the journaling version of ext2 file systems An error table compiler; it converts a table of error-code names and messages into a C source file suitable for use with the com_err library A file system debugger; it can be used to examine and change the state of an ext2 file system Prints the super block and blocks group information for the file system present on a given device Reports free space fragmentation information Is used to check, and optionally repair ext2 file systems and ext3 file systems Is used to save critical ext2 file system data to a file Prints the FS type of a given filesystem, given either a device name or label Displays or changes the file system label on the ext2 file system present on a given device Replays the undo log undo_log for an ext2/ext3/ext4 filesystem found on a device. This can be used to undo a failed operation by an e2fsprogs program. Reports on how badly fragmented a particular file might be 117

Linux From Scratch - Version 6.7 fsck.ext2 fsck.ext3 fsck.ext4 fsck.ext4dev logsave lsattr mk_cmds mke2fs mkfs.ext2 mkfs.ext3 mkfs.ext4 mkfs.ext4dev mklost+found resize2fs tune2fs libcom_err libe2p libext2fs libss By default checks ext2 file systems. This is a hard link to e2fsck. By default checks ext3 file systems. This is a hard link to e2fsck. By default checks ext4 file systems. This is a hard link to e2fsck. By default checks ext4 development file systems. This is a hard link to e2fsck. Saves the output of a command in a log file Lists the attributes of files on a second extended file system Converts a table of command names and help messages into a C source file suitable for use with the libss subsystem library Creates an ext2 or ext3 file system on the given device By default creates ext2 file systems. This is a hard link to mke2fs. By default creates ext3 file systems. This is a hard link to mke2fs. By default creates ext4 file systems. This is a hard link to mke2fs. By default creates ext4 development file systems. This is a hard link to mke2fs. Used to create a lost+found directory on an ext2 file system; it pre-allocates disk blocks to this directory to lighten the task of e2fsck Can be used to enlarge or shrink an ext2 file system Adjusts tunable file system parameters on an ext2 file system The common error display routine Used by dumpe2fs, chattr, and lsattr Contains routines to enable user-level programs to manipulate an ext2 file system Used by debugfs

6.22.1. Installation of Coreutils
A known issue with the uname program from this package is that the -p switch always returns unknown. The following patch fixes this behavior for Intel architectures: case `uname -m` in i?86 | x86_64) patch -Np1 -i ../coreutils-8.5-uname-2.patch ;; esac POSIX requires that programs from Coreutils recognize character boundaries correctly even in multibyte locales. The following patch fixes this non-compliance and other internationalization-related bugs: patch -Np1 -i ../coreutils-8.5-i18n-1.patch

Note
In the past, many bugs were found in this patch. When reporting new bugs to Coreutils maintainers, please check first if they are reproducible without this patch. Now prepare Coreutils for compilation: ./configure --prefix=/usr \ --enable-no-install-program=kill,uptime
The meaning of the configure options:

--enable-no-install-program=kill,uptime The purpose of this switch is to prevent Coreutils from installing binaries that will be installed by other packages later. Compile the package: make Skip down to “Install the package” if not running the test suite. Now the test suite is ready to be run. First, run the tests that are meant to be run as user root: make NON_ROOT_USERNAME=nobody check-root We're going to run the remainder of the tests as the nobody user. Certain tests, however, require that the user be a member of more than one group. So that these tests are not skipped we'll add a temporary group and make the user nobody a part of it: echo "dummy:x:1000:nobody" >> /etc/group 119

Some of the scripts in the LFS-Bootscripts package depend on head, sleep, and nice. As /usr may not be available during the early stages of booting, those binaries need to be on the root partition: mv -v /usr/bin/{head,sleep,nice} /bin

Short Descriptions
base64 basename cat chcon chgrp chmod Encodes and decodes data according to the base64 (RFC 3548) specification Strips any path and a given suffix from a file name Concatenates files to standard output Changes security context for files and directories Changes the group ownership of files and directories Changes the permissions of each file to the given mode; the mode can be either a symbolic representation of the changes to make or an octal number representing the new permissions 120

Linux From Scratch - Version 6.7 chown chroot cksum comm cp csplit cut date dd df dir dircolors dirname du echo env expand expr factor false fmt fold groups head hostid id install join link ln logname ls md5sum Changes the user and/or group ownership of files and directories Runs a command with the specified directory as the / directory Prints the Cyclic Redundancy Check (CRC) checksum and the byte counts of each specified file Compares two sorted files, outputting in three columns the lines that are unique and the lines that are common Copies files Splits a given file into several new files, separating them according to given patterns or line numbers and outputting the byte count of each new file Prints sections of lines, selecting the parts according to given fields or positions Displays the current time in the given format, or sets the system date Copies a file using the given block size and count, while optionally performing conversions on it Reports the amount of disk space available (and used) on all mounted file systems, or only on the file systems holding the selected files Lists the contents of each given directory (the same as the ls command) Outputs commands to set the LS_COLOR environment variable to change the color scheme used by ls Strips the non-directory suffix from a file name Reports the amount of disk space used by the current directory, by each of the given directories (including all subdirectories) or by each of the given files Displays the given strings Runs a command in a modified environment Converts tabs to spaces Evaluates expressions Prints the prime factors of all specified integer numbers Does nothing, unsuccessfully; it always exits with a status code indicating failure Reformats the paragraphs in the given files Wraps the lines in the given files Reports a user's group memberships Prints the first ten lines (or the given number of lines) of each given file Reports the numeric identifier (in hexadecimal) of the host Reports the effective user ID, group ID, and group memberships of the current user or specified user Copies files while setting their permission modes and, if possible, their owner and group Joins the lines that have identical join fields from two separate files Creates a hard link with the given name to a file Makes hard links or soft (symbolic) links between files Reports the current user's login name Lists the contents of each given directory Reports or checks Message Digest 5 (MD5) checksums 121

Linux From Scratch - Version 6.7 mkdir mkfifo mknod mktemp mv nice nl nohup nproc od paste pathchk pinky pr printenv printf ptx pwd readlink rm rmdir runcon seq sha1sum sha224sum sha256sum sha384sum sha512sum shred shuf sleep sort split stat Creates directories with the given names Creates First-In, First-Outs (FIFOs), a “named pipe” in UNIX parlance, with the given names Creates device nodes with the given names; a device node is a character special file, a block special file, or a FIFO Creates temporary files in a secure manner; it is used in scripts Moves or renames files or directories Runs a program with modified scheduling priority Numbers the lines from the given files Runs a command immune to hangups, with its output redirected to a log file Prints the number of processing units available to a process Dumps files in octal and other formats Merges the given files, joining sequentially corresponding lines side by side, separated by tab characters Checks if file names are valid or portable Is a lightweight finger client; it reports some information about the given users Paginates and columnates files for printing Prints the environment Prints the given arguments according to the given format, much like the C printf function Produces a permuted index from the contents of the given files, with each keyword in its context Reports the name of the current working directory Reports the value of the given symbolic link Removes files or directories Removes directories if they are empty Runs a command with specified security context Prints a sequence of numbers within a given range and with a given increment Prints or checks 160-bit Secure Hash Algorithm 1 (SHA1) checksums Prints or checks 224-bit Secure Hash Algorithm checksums Prints or checks 256-bit Secure Hash Algorithm checksums Prints or checks 384-bit Secure Hash Algorithm checksums Prints or checks 512-bit Secure Hash Algorithm checksums Overwrites the given files repeatedly with complex patterns, making it difficult to recover the data Shuffles lines of text Pauses for the given amount of time Sorts the lines from the given files Splits the given file into pieces, by size or by number of lines Displays file or filesystem status 122

Linux From Scratch - Version 6.7 stdbuf stty sum sync tac tail tee test timeout touch tr true truncate tsort tty uname unexpand uniq unlink users vdir wc who whoami yes libstdbuf Runs commands with altered buffering operations for its standard streams Sets or reports terminal line settings Prints checksum and block counts for each given file Flushes file system buffers; it forces changed blocks to disk and updates the super block Concatenates the given files in reverse Prints the last ten lines (or the given number of lines) of each given file Reads from standard input while writing both to standard output and to the given files Compares values and checks file types Runs a command with a time limit Changes file timestamps, setting the access and modification times of the given files to the current time; files that do not exist are created with zero length Translates, squeezes, and deletes the given characters from standard input Does nothing, successfully; it always exits with a status code indicating success Shrinks or expands a file to the specified size Performs a topological sort; it writes a completely ordered list according to the partial ordering in a given file Reports the file name of the terminal connected to standard input Reports system information Converts spaces to tabs Discards all but one of successive identical lines Removes the given file Reports the names of the users currently logged on Is the same as ls -l Reports the number of lines, words, and bytes for each given file, as well as a total line when more than one file is given Reports who is logged on Reports the user name associated with the current effective user ID Repeatedly outputs “y” or a given string until killed Library used by stdbuf

6.23.1. Installation of Iana-Etc
The following command converts the raw data provided by IANA into the correct formats for the /etc/protocols and /etc/services data files: make This package does not come with a test suite. Install the package: make install

Short Descriptions
/etc/protocols /etc/services Describes the various DARPA Internet protocols that are available from the TCP/IP subsystem Provides a mapping between friendly textual names for internet services, and their underlying assigned port numbers and protocol types

6.24.1. Installation of M4
Add a missing include directive that prevents M4 successfully building against Glibc-2.12.1: sed -i -e '/"m4.h"/a\ #include <sys/stat.h>' src/path.c Prepare M4 for compilation: ./configure --prefix=/usr Compile the package: make To test the results, issue: make check Install the package: make install

6.24.2. Contents of M4
Installed program: m4

Short Descriptions
m4 copies the given files while expanding the macros that they contain. These macros are either built-in or user-defined and can take any number of arguments. Besides performing macro expansion, m4 has built-in functions for including named files, running Unix commands, performing integer arithmetic, manipulating text, recursion, etc. The m4 program can be used either as a front-end to a compiler or as a macro processor in its own right.

6.25.1. Installation of Bison
Prepare Bison for compilation: ./configure --prefix=/usr The configure system causes Bison to be built without support for internationalization of error messages if a bison program is not already in $PATH. The following addition will correct this: echo '#define YYENABLE_NLS 1' >> lib/config.h Compile the package: make To test the results (about 0.5 SBU), issue: make check Install the package: make install

Short Descriptions
bison yacc liby.a Generates, from a series of rules, a program for analyzing the structure of text files; Bison is a replacement for Yacc (Yet Another Compiler Compiler) A wrapper for bison, meant for programs that still call yacc instead of bison; it calls bison with the -y option The Yacc library containing implementations of Yacc-compatible yyerror and main functions; this library is normally not very useful, but POSIX requires it

6.26.1. Installation of Procps
Apply a patch to fix a unicode related issue in the watch program: patch -Np1 -i ../procps-3.2.8-watch_unicode-1.patch Fix a bug in the Makefile, which prevents procps from building with make-3.82: sed -i -e 's@\*/module.mk@proc/module.mk ps/module.mk@' Makefile Compile the package: make This package does not come with a test suite. Install the package: make install

Short Descriptions
free kill pgrep pkill pmap ps pwdx skill slabtop snice sysctl tload top Reports the amount of free and used memory (both physical and swap memory) in the system Sends signals to processes Looks up processes based on their name and other attributes Signals processes based on their name and other attributes Reports the memory map of the given process Lists the current running processes Reports the current working directory of a process Sends signals to processes matching the given criteria Displays detailed kernel slap cache information in real time Changes the scheduling priority of processes matching the given criteria Modifies kernel parameters at run time Prints a graph of the current system load average Displays a list of the most CPU intensive processes; it provides an ongoing look at processor activity in real time 127

Linux From Scratch - Version 6.7 uptime vmstat w watch libproc Reports how long the system has been running, how many users are logged on, and the system load averages Reports virtual memory statistics, giving information about processes, memory, paging, block Input/Output (IO), traps, and CPU activity Shows which users are currently logged on, where, and since when Runs a given command repeatedly, displaying the first screen-full of its output; this allows a user to watch the output change over time Contains the functions used by most programs in this package

6.28.1. Installation of Readline
Reinstalling Readline will cause the old libraries to be moved to <libraryname>.old. While this is normally not a problem, in some cases it can trigger a linking bug in ldconfig. This can be avoided by issuing the following two seds: sed -i '/MV.*old/d' Makefile.in sed -i '/{OLDSUFF}/c:' support/shlib-install Correct the version number used in Readline's documentation: sed -i -e 's/0x0600/0x0601/' \ -e 's/6\.0/6.1/' \ -e 's/RL_VERSION_MINOR\t0/RL_VERSION_MINOR\t1/' readline.h Prepare Readline for compilation: ./configure --prefix=/usr --libdir=/lib Compile the package: make SHLIB_LIBS=-lncurses
The meaning of the make option:

Short Descriptions
libhistory Provides a consistent user interface for recalling lines of history libreadline Aids in the consistency of user interface across discrete programs that need to provide a command line interface

--htmldir This option designates the directory into which HTML formatted documentation will be installed. --with-installed-readline This option tells Bash to use the readline library that is already installed on the system rather than using its own readline version. Compile the package: make Skip down to “Install the package” if not running the test suite. To prepare the tests, ensure that the nobody user can write to the sources tree: chown -Rv nobody . Now, run the tests as the nobody user: su-tools nobody -s /bin/bash -c "make tests" Install the package: make install Run the newly compiled bash program (replacing the one that is currently being executed): exec /bin/bash --login +h

Note
The parameters used make the bash process an interactive login shell and continue to disable hashing so that new programs are found as they become available. 132

Short Descriptions
bash bashbug sh A widely-used command interpreter; it performs many types of expansions and substitutions on a given command line before executing it, thus making this interpreter a powerful tool A shell script to help the user compose and mail standard formatted bug reports concerning bash A symlink to the bash program; when invoked as sh, bash tries to mimic the startup behavior of historical versions of sh as closely as possible, while conforming to the POSIX standard as well

Short Descriptions
libtool libtoolize libltdl Provides generalized library-building support services Provides a standard way to add libtool support to a package Hides the various difficulties of dlopening libraries

134

Linux From Scratch - Version 6.7

6.31. GDBM-1.8.3
The GDBM package contains the GNU Database Manager. This is a disk file format database which stores key/data-pairs in single files. The actual data of any record being stored is indexed by a unique key, which can be retrieved in less time than if it was stored in a text file. Approximate build time: Required disk space: 0.1 SBU 2.7 MB

6.31.1. Installation of GDBM
Prepare GDBM for compilation: ./configure --prefix=/usr Compile the package: make This package does not come with a test suite. Install the package: make install In addition, install the DBM and NDBM compatibility headers, as some packages outside of LFS may look for these older dbm routines: make install-compat Fix a minor installation issue by manually adding GDBM to the info table of contents: install-info --dir-file=/usr/info/dir /usr/info/gdbm.info

--disable-ifconfig This option prevents Inetutils from installing the ifconfig program, which can be used to configure network interfaces. LFS uses ip from IPRoute2 to perform this task. --disable-logger This option prevents Inetutils from installing the logger program, which is used by scripts to pass messages to the System Log Daemon. Do not install it because Util-linux installed a version earlier. --disable-syslogd This option prevents Inetutils from installing the System Log Daemon, which is installed with the Sysklogd package. --disable-whois This option disables the building of the Inetutils whois client, which is out of date. Instructions for a better whois client are in the BLFS book. --disable-servers This disables the installation of the various network servers included as part of the Inetutils package. These servers are deemed not appropriate in a basic LFS system. Some are insecure by nature and are only considered safe on trusted networks. More information can be found at http://www.linuxfromscratch. org/blfs/view/svn/basicnet/inetutils.html. Note that better replacements are available for many of these servers. Compile the package: make This package does not come with a test suite. Install the package: make install Move some programs to their FHS-compliant place: mv -v /usr/bin/{hostname,ping,ping6} /bin mv -v /usr/bin/traceroute /sbin

Short Descriptions
ftp hostname ping ping6 rcp rexec rlogin rsh talk telnet tftp traceroute Is the file transfer protocol program Reports or sets the name of the host Sends echo-request packets and reports how long the replies take A version of ping for IPv6 networks Performs remote file copy executes commands on a remote host Performs remote login Runs a remote shell Is used to chat with another user An interface to the TELNET protocol A trivial file transfer program Traces the route your packets take from the host you are working on to another host on a network, showing all the intermediate hops (gateways) along the way

6.33.1. Installation of Perl
First create a basic /etc/hosts file to be referenced in one of Perl's configuration files as well as the optional test suite: echo "127.0.0.1 localhost $(hostname)" > /etc/hosts This version of Perl now builds the Compress::Raw::Zlib module. By default Perl will use an internal copy of the Zlib source for the build. Issue the following command so that Perl will use the Zlib library installed on the system: sed -i -e "s|BUILD_ZLIB\s*= True|BUILD_ZLIB = False|" \ -e "s|INCLUDE\s*= ./zlib-src|INCLUDE = /usr/include|" \ -e "s|LIB\s*= ./zlib-src|LIB = /usr/lib|" \ cpan/Compress-Raw-Zlib/config.in To have full control over the way Perl is set up, you can remove the “-des” options from the following command and hand-pick the way this package is built. Alteratively, use the command exactly as below to use the defaults that Perl auto-detects: sh Configure -des -Dprefix=/usr \ -Dvendorprefix=/usr -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 -Dpager="/usr/bin/less -isR" -Duseshrplib
The meaning of the configure options:

\ \ \ \

-Dvendorprefix=/usr This ensures perl knows how to tell packages where they should install their perl modules. -Dpager="/usr/bin/less -isR" This corrects an error in the way that perldoc invokes the less program. -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 Since Groff is not installed yet, Configure thinks that we do not want man pages for Perl. Issuing these parameters overrides this decision. -Duseshrplib Build a shared libperl needed by some perl modules. Compile the package: make To test the results (approximately 2.5 SBU), issue: make test 138

Short Descriptions
a2p c2ph config_data corelist cpan cpan2dist cpanp cpanp-run-perl dprofpp enc2xs find2perl h2ph h2xs instmodsh libnetcfg perl perl5.12.1 perlbug perldoc perlivp perlthanks Translates awk to Perl Dumps C structures as generated from cc -g -S Queries or changes configuration of Perl modules A commandline frontend to Module::CoreList Interact with the Comprehensive Perl Archive Network (CPAN) from the command line The CPANPLUS distribution creator The CPANPLUS launcher Perl script that is used to enable flushing of the output buffer after each write in spawned processes Displays Perl profile data Builds a Perl extension for the Encode module from either Unicode Character Mappings or Tcl Encoding Files Translates find commands to Perl Converts .h C header files to .ph Perl header files Converts .h C header files to Perl extensions Shell script for examining installed Perl modules, and can even create a tarball from an installed module Can be used to configure the libnet Combines some of the best features of C, sed, awk and sh into a single swiss-army language A hard link to perl Used to generate bug reports about Perl, or the modules that come with it, and mail them Displays a piece of documentation in pod format that is embedded in the Perl installation tree or in a Perl script The Perl Installation Verification Procedure; it can be used to verify that Perl and its libraries have been installed correctly Used to generate thank you messages to mail to the Perl developers 139

6.34.1. Installation of Autoconf
Prepare Autoconf for compilation: ./configure --prefix=/usr Compile the package: make To test the results, issue: make check This takes a long time, about 4.7 SBUs. In addition, 6 tests are skipped that use Automake. For full test coverage, Autoconf can be re-tested after Automake has been installed. Install the package: make install

Short Descriptions
autoconf Produces shell scripts that automatically configure software source code packages to adapt to many kinds of Unix-like systems. The configuration scripts it produces are independent—running them does not require the autoconf program. A tool for creating template files of C #define statements for configure to use A wrapper for the M4 macro processor Automatically runs autoconf, autoheader, aclocal, automake, gettextize, and libtoolize in the correct order to save time when changes are made to autoconf and automake template files Helps to create a configure.in file for a software package; it examines the source files in a directory tree, searching them for common portability issues, and creates a configure.scan file that serves as as a preliminary configure.in file for the package Modifies a configure.in file that still calls autoconf macros by their old names to use the current macro names Helps when writing configure.in files for a software package; it prints the identifiers that the package uses in C preprocessor conditionals. If a package has already been set up to have some portability, this program can help determine what configure needs to check for. It can also fill in gaps in a configure.in file generated by autoscan 141

6.35.1. Installation of Automake
Prepare Automake for compilation: ./configure --prefix=/usr --docdir=/usr/share/doc/automake-1.11.1 Compile the package: make To test the results, issue: make check This takes a long time, about 10 SBUs. Install the package: make install

Short Descriptions
acinstall aclocal aclocal-1.11.1 automake A script that installs aclocal-style M4 files Generates aclocal.m4 files based on the contents of configure.in files A hard link to aclocal A tool for automatically generating Makefile.in files from Makefile.am files. To create all the Makefile.in files for a package, run this program in the top-level directory. By scanning the configure.in file, it automatically finds each appropriate Makefile. am file and generates the corresponding Makefile.in file A hard link to automake A wrapper for compilers A script that attempts to guess the canonical triplet for the given build, host, or target architecture A configuration validation subroutine script A script for compiling a program so that dependency information is generated in addition to the desired output 142

automake-1.11.1 compile config.guess config.sub depcomp

Linux From Scratch - Version 6.7 elisp-comp install-sh mdate-sh missing mkinstalldirs py-compile symlink-tree ylwrap Byte-compiles Emacs Lisp code A script that installs a program, script, or data file A script that prints the modification time of a file or directory A script acting as a common stub for missing GNU programs during an installation A script that creates a directory tree Compiles a Python program A script to create a symlink tree of a directory tree A wrapper for lex and yacc

6.36.1. Installation of Bzip2
Apply 2 patches that will install the documentation for this package and correct some hard-coded version numbers: patch -Np1 -i ../bzip2-1.0.5-install_docs-1.patch patch -Np1 -i ../bzip2-1.0.5-version_fixes-1.patch The following command ensures installation of symbolic links are relative: sed -i 's@\(ln -s -f \)$(PREFIX)/bin/@\1@' Makefile Prepare Bzip2 for compilation with: make -f Makefile-libbz2_so make clean
The meaning of the make parameter:

-f Makefile-libbz2_so This will cause Bzip2 to be built using a different Makefile file, in this case the Makefile-libbz2_so file, which creates a dynamic libbz2.so library and links the Bzip2 utilities against it. Compile and test the package: make Install the programs: make PREFIX=/usr install Install the shared bzip2 binary into the /bin directory, make some necessary symbolic links, and clean up: cp cp ln rm ln ln -v bzip2-shared /bin/bzip2 -av libbz2.so* /lib -sv ../../lib/libbz2.so.1.0 /usr/lib/libbz2.so -v /usr/bin/{bunzip2,bzcat,bzip2} -sv bzip2 /bin/bunzip2 -sv bzip2 /bin/bzcat

Short Descriptions
cmp diff diff3 sdiff Compares two files and reports whether or in which bytes they differ Compares two files or directories and reports which lines in the files differ Compares three files line by line Merges two files and interactively outputs the results

Short Descriptions
awk gawk gawk-3.1.8 grcat igawk pgawk pgawk-3.1.8 pwcat A link to gawk A program for manipulating text files; it is the GNU implementation of awk A hard link to gawk Dumps the group database /etc/group Gives gawk the ability to include files The profiling version of gawk Hard link to pgawk Dumps the password database /etc/passwd

Short Descriptions
file Tries to classify each given file; it does this by performing several tests—file system tests, magic number tests, and language tests

libmagic Contains routines for magic number recognition, used by the file program

148

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6.40. Findutils-4.4.2
The Findutils package contains programs to find files. These programs are provided to recursively search through a directory tree and to create, maintain, and search a database (often faster than the recursive find, but unreliable if the database has not been recently updated). Approximate build time: Required disk space: 0.5 SBU 22 MB

--localstatedir This option changes the location of the locate database to be in /var/lib/locate, which is FHS-compliant. Compile the package: make To test the results, issue: make check Install the package: make install Some of the scripts in the LFS-Bootscripts package depend on find. As /usr may not be available during the early stages of booting, this program needs to be on the root partition. The updatedb script also needs to be modified to correct an explicit path: mv -v /usr/bin/find /bin sed -i 's/find:=${BINDIR}/find:=\/bin/' /usr/bin/updatedb

Short Descriptions
bigram code find frcode Was formerly used to produce locate databases Was formerly used to produce locate databases; it is the ancestor of frcode. Searches given directory trees for files matching the specified criteria Is called by updatedb to compress the list of file names; it uses front-compression, reducing the database size by a factor of four to five. 149

Linux From Scratch - Version 6.7 locate oldfind updatedb xargs Searches through a database of file names and reports the names that contain a given string or match a given pattern Older version of find, using a different algorithm Updates the locate database; it scans the entire file system (including other file systems that are currently mounted, unless told not to) and puts every file name it finds into the database Can be used to apply a given command to a list of files

Short Descriptions
flex lex libfl.a A tool for generating programs that recognize patterns in text; it allows for the versatility to specify the rules for pattern-finding, eradicating the need to develop a specialized program A script that runs flex in lex emulation mode The flex library

6.42.1. Installation of Gettext
Prepare Gettext for compilation: ./configure --prefix=/usr \ --docdir=/usr/share/doc/gettext-0.18.1.1 Compile the package: make To test the results (this takes a long time, around 3 SBUs), issue: make check Install the package: make install

Short Descriptions
autopoint config.charset config.rpath envsubst gettext gettext.sh gettextize hostname Copies standard Gettext infrastructure files into a source package Outputs a system-dependent table of character encoding aliases Outputs a system-dependent set of variables, describing how to set the runtime search path of shared libraries in an executable Substitutes environment variables in shell format strings Translates a natural language message into the user's language by looking up the translation in a message catalog Primarily serves as a shell function library for gettext Copies all standard Gettext files into the given top-level directory of a package to begin internationalizing it Displays a network hostname in various forms 153

Linux From Scratch - Version 6.7 msgattrib msgcat msgcmp msgcomm msgconv msgen msgexec msgfilter msgfmt msggrep msginit msgmerge msgunfmt msguniq ngettext recode-sr-latin xgettext libasprintf libgettextlib libgettextpo Filters the messages of a translation catalog according to their attributes and manipulates the attributes Concatenates and merges the given .po files Compares two .po files to check that both contain the same set of msgid strings Finds the messages that are common to to the given .po files Converts a translation catalog to a different character encoding Creates an English translation catalog Applies a command to all translations of a translation catalog Applies a filter to all translations of a translation catalog Generates a binary message catalog from a translation catalog Extracts all messages of a translation catalog that match a given pattern or belong to some given source files Creates a new .po file, initializing the meta information with values from the user's environment Combines two raw translations into a single file Decompiles a binary message catalog into raw translation text Unifies duplicate translations in a translation catalog Displays native language translations of a textual message whose grammatical form depends on a number Recodes Serbian text from Cyrillic to Latin script Extracts the translatable message lines from the given source files to make the first translation template defines the autosprintf class, which makes C formatted output routines usable in C++ programs, for use with the <string> strings and the <iostream> streams a private library containing common routines used by the various Gettext programs; these are not intended for general use Used to write specialized programs that process .po files; this library is used when the standard applications shipped with Gettext (such as msgcomm, msgcmp, msgattrib, and msgen) will not suffice A private library containing common routines used by the various Gettext programs; these are not intended for general use A library, intended to be used by LD_PRELOAD that assists libintl in logging untranslated messages.

6.43.1. Installation of Groff
Groff expects the environment variable PAGE to contain the default paper size. For users in the United States, PAGE=letter is appropriate. Elsewhere, PAGE=A4 may be more suitable. While the default paper size is configured during compilation, it can be overridden later by echoing either “A4” or “letter” to the /etc/papersize file. Prepare Groff for compilation: PAGE=<paper_size> ./configure --prefix=/usr Compile the package: make This package does not come with a test suite. Install the package: make docdir=/usr/share/doc/groff-1.20.1 install Some documentation programs, such as xman, will not work properly without the following symlinks: ln -sv eqn /usr/bin/geqn ln -sv tbl /usr/bin/gtbl

Short Descriptions
addftinfo afmtodit chem eqn eqn2graph Reads a troff font file and adds some additional font-metric information that is used by the groff system Creates a font file for use with groff and grops Groff preprocessor for producing chemical structure diagrams Compiles descriptions of equations embedded within troff input files into commands that are understood by troff Converts a troff EQN (equation) into a cropped image 155

Linux From Scratch - Version 6.7 gdiffmk geqn grap2graph grn grodvi groff groffer grog grolbp grolj4 grops grotty gtbl hpftodit indxbib lkbib lookbib Marks differences between groff/nroff/troff files A link to eqn Converts a grap diagram into a cropped bitmap image A groff preprocessor for gremlin files A driver for groff that produces TeX dvi format A front-end to the groff document formatting system; normally, it runs the troff program and a post-processor appropriate for the selected device Displays groff files and man pages on X and tty terminals Reads files and guesses which of the groff options -e, -man, -me, -mm, -ms, -p, -s, and -t are required for printing files, and reports the groff command including those options Is a groff driver for Canon CAPSL printers (LBP-4 and LBP-8 series laser printers) Is a driver for groff that produces output in PCL5 format suitable for an HP LaserJet 4 printer Translates the output of GNU troff to PostScript Translates the output of GNU troff into a form suitable for typewriter-like devices A link to tbl Creates a font file for use with groff -Tlj4 from an HP-tagged font metric file Creates an inverted index for the bibliographic databases with a specified file for use with refer, lookbib, and lkbib Searches bibliographic databases for references that contain specified keys and reports any references found Prints a prompt on the standard error (unless the standard input is not a terminal), reads a line containing a set of keywords from the standard input, searches the bibliographic databases in a specified file for references containing those keywords, prints any references found on the standard output, and repeats this process until the end of input A simple preprocessor for groff Formats equations for American Standard Code for Information Interchange (ASCII) output A script that emulates the nroff command using groff Creates pdf documents using groff Translates a PostScript font in .pfb format to ASCII Compiles descriptions of pictures embedded within troff or TeX input files into commands understood by TeX or troff Converts a PIC diagram into a cropped image Translates the output of GNU troff to HTML Converts encoding of input files to something GNU troff understands Translates the output of GNU troff to HTML Copies the contents of a file to the standard output, except that lines between .[ and .] are interpreted as citations, and lines between .R1 and .R2 are interpreted as commands for how citations are to be processed 156

Linux From Scratch - Version 6.7 roff2dvi roff2html roff2pdf roff2ps roff2text roff2x soelim tbl tfmtodit troff Transforms roff files into DVI format Transforms roff files into HTML format Transforms roff files into PDFs Transforms roff files into ps files Transforms roff files into text files Transforms roff files into other formats Reads files and replaces lines of the form .so file by the contents of the mentioned file Compiles descriptions of tables embedded within troff input files into commands that are understood by troff Creates a font file for use with groff -Tdvi Is highly compatible with Unix troff; it should usually be invoked using the groff command, which will also run preprocessors and post-processors in the appropriate order and with the appropriate options

6.44.1. Installation of GRUB
Prepare GRUB for compilation: ./configure --prefix=/usr \ --sysconfdir=/etc \ --disable-grub-emu-usb \ --disable-grub-fstest \ --disable-efiemu The --disable switches minimize what is built by disabling features and testing programs not really needed for LFS. Compile the package: make This package does not come with a test suite. Install the package: make install Using GRUB to make your LFS system bootable will be discussed in Section 8.4, “Using GRUB to Set Up the Boot Process”.

Linux From Scratch - Version 6.7 grub-mkpasswd-pbkdf2 grub-mkrelpath grub-mkrescue grub-probe grub-reboot grub-script-check grub-set-default grub-setup Generates an encrypted PBKDF2 password for use in the boot menu Makes a system pathname relative to its root Make a bootable image of GRUB suitable for a floppy disk Probe device information for a given path or device Sets the default boot entry for GRUB for the next boot only Checks GRUB configuration script for syntax errors Sets the default boot entry for GRUB Set up images to boot from a device

6.45.1. Installation of Gzip
Prepare Gzip for compilation: ./configure --prefix=/usr --bindir=/bin Compile the package: make To test the results, issue: make check Install the package: make install Move some programs that do not need to be on the root filesystem: mv -v /bin/{gzexe,uncompress,zcmp,zdiff,zegrep} /usr/bin mv -v /bin/{zfgrep,zforce,zgrep,zless,zmore,znew} /usr/bin

6.46.1. Installation of IPRoute2
The arpd binary included in this package is dependent on Berkeley DB. Because arpd is not a very common requirement on a base Linux system, remove the dependency on Berkeley DB by applying the sed command below. If the arpd binary is needed, instructions for compiling Berkeley DB can be found in the BLFS Book at http://www. linuxfromscratch.org/blfs/view/svn/server/databases.html#db. sed -i '/^TARGETS/s@arpd@@g' misc/Makefile Fix a bug that causes the ip route get command to not produce any output: sed -i '1289i\\tfilter.cloned = 2;' ip/iproute.c Compile the package: make DESTDIR=
The meaning of the make option:

DESTDIR= This ensures that the IPRoute2 binaries will install into the correct directory. By default, DESTDIR is set to /usr. This package comes with a test suite, but due to assumptions it makes, it is not possible to reliably run these tests from within the chroot environment. If you wish to run these tests after booting into your new LFS system, ensure you select /proc/config.gz CONFIG_IKCONFIG_PROC ("General setup" -> "Enable access to .config through /proc/config.gz") support into your kernel then run 'make alltests' from the testsuite/ subdirectory. Install the package: make DESTDIR= SBINDIR=/sbin MANDIR=/usr/share/man \ DOCDIR=/usr/share/doc/iproute2-2.6.35 install

Short Descriptions
ctstat genl ifcfg A shell script wrapper for the ip command. Note that it requires the arping and rdisk programs from the iputils package found at http://www.skbuff.net/iputils/. 162 Connection status utility

Linux From Scratch - Version 6.7 ifstat ip Shows the interface statistics, including the amount of transmitted and received packets by interface The main executable. It has several different functions: ip link <device> allows users to look at the state of devices and to make changes ip addr allows users to look at addresses and their properties, add new addresses, and delete old ones ip neighbor allows users to look at neighbor bindings and their properties, add new neighbor entries, and delete old ones ip rule allows users to look at the routing policies and change them ip route allows users to look at the routing table and change routing table rules ip tunnel allows users to look at the IP tunnels and their properties, and change them ip maddr allows users to look at the multicast addresses and their properties, and change them ip mroute allows users to set, change, or delete the multicast routing ip monitor allows users to continously monitor the state of devices, addresses and routes Provides Linux network statistics. It is a generalized and more feature-complete replacement for the old rtstat program Shows network statistics A component of ip route. This is for flushing the routing tables A component of ip route. This is for listing the routing tables Displays the contents of /proc/net/rt_acct Route monitoring utility Converts the output of ip -o back into a readable form Route status utility Similar to the netstat command; shows active connections Traffic Controlling Executable; this is for Quality Of Service (QOS) and Class Of Service (COS) implementations tc qdisc allows users to setup the queueing discipline tc class allows users to setup classes based on the queuing discipline scheduling tc estimator allows users to estimate the network flow into a network tc filter allows users to setup the QOS/COS packet filtering tc policy allows users to setup the QOS/COS policies

6.47.1. Installation of Kbd
The behaviour of the Backspace and Delete keys is not consistent across the keymaps in the Kbd package. The following patch fixes this issue for i386 keymaps: patch -Np1 -i ../kbd-1.15.2-backspace-1.patch After patching, the Backspace key generates the character with code 127, and the Delete key generates a well-known escape sequence. Prepare Kbd for compilation: ./configure --prefix=/usr --datadir=/lib/kbd
The meaning of the configure options:

--datadir=/lib/kbd This option puts keyboard layout data in a directory that will always be on the root partition instead of the default /usr/share/kbd. Compile the package: make This package does not come with a test suite. Install the package: make install

Note
For some languages (e.g., Belarusian) the Kbd package doesn't provide a useful keymap where the stock “by” keymap assumes the ISO-8859-5 encoding, and the CP1251 keymap is normally used. Users of such languages have to download working keymaps separately. Some of the scripts in the LFS-Bootscripts package depend on kbd_mode, loadkeys, openvt, and setfont. As /usr may not be available during the early stages of booting, those binaries need to be on the root partition: mv -v /usr/bin/{kbd_mode,loadkeys,openvt,setfont} /bin If desired, install the documentation: mkdir -v /usr/share/doc/kbd-1.15.2 cp -R -v doc/* \ /usr/share/doc/kbd-1.15.2 164

Short Descriptions
chvt deallocvt dumpkeys fgconsole getkeycodes kbd_mode kbdrate loadkeys loadunimap mapscrn openvt psfaddtable psfgettable psfstriptable psfxtable resizecons setfont setkeycodes setleds setmetamode showconsolefont showkey unicode_start Changes the foreground virtual terminal Deallocates unused virtual terminals Dumps the keyboard translation tables Prints the number of the active virtual terminal Prints the kernel scancode-to-keycode mapping table Reports or sets the keyboard mode Sets the keyboard repeat and delay rates Loads the keyboard translation tables Loads the kernel unicode-to-font mapping table An obsolete program that used to load a user-defined output character mapping table into the console driver; this is now done by setfont Starts a program on a new virtual terminal (VT) A link to psfxtable A link to psfxtable A link to psfxtable Handle Unicode character tables for console fonts Changes the kernel idea of the console size Changes the Enhanced Graphic Adapter (EGA) and Video Graphics Array (VGA) fonts on the console Loads kernel scancode-to-keycode mapping table entries; this is useful if there are unusual keys on the keyboard Sets the keyboard flags and Light Emitting Diodes (LEDs) Defines the keyboard meta-key handling Shows the current EGA/VGA console screen font Reports the scancodes, keycodes, and ASCII codes of the keys pressed on the keyboard Puts the keyboard and console in UNICODE mode. Don't use this program unless your keymap file is in the ISO-8859-1 encoding. For other encodings, this utility produces incorrect results. Reverts keyboard and console from UNICODE mode

6.48.1. Installation of Less
Prepare Less for compilation: ./configure --prefix=/usr --sysconfdir=/etc
The meaning of the configure options:

--sysconfdir=/etc This option tells the programs created by the package to look in /etc for the configuration files. Compile the package: make This package does not come with a test suite. Install the package: make install

6.48.2. Contents of Less
Installed programs: less, lessecho, and lesskey

Short Descriptions
less lessecho lesskey A file viewer or pager; it displays the contents of the given file, letting the user scroll, find strings, and jump to marks Needed to expand meta-characters, such as * and ?, in filenames on Unix systems Used to specify the key bindings for less

--disable-setuid This disables making the man program setuid to user man. --with-... These three parameters are used to set some default programs. lynx is a text-based web browser (see BLFS for installation instructions), vgrind converts program sources to Groff input, and grap is useful for typesetting graphs in Groff documents. The vgrind and grap programs are not normally needed for viewing manual pages. They are not part of LFS or BLFS, but you should be able to install them yourself after finishing LFS if you wish to do so. Compile the package: make To test the results, issue: make check Install the package: make install

6.50.2. Non-English Manual Pages in LFS
The following table shows the character set that Man-DB assumes manual pages installed under /usr/share/man/<ll> will be encoded with. In addition to this, Man-DB correctly determines if manual pages installed in that directory are UTF-8 encoded.

Short Descriptions
accessdb Dumps the whatis database contents in human-readable form 169

Linux From Scratch - Version 6.7 apropos catman lexgrog man mandb manpath whatis zsoelim Searches the whatis database and displays the short descriptions of system commands that contain a given string Creates or updates the pre-formatted manual pages Displays one-line summary information about a given manual page Formats and displays the requested manual page Creates or updates the whatis database Displays the contents of $MANPATH or (if $MANPATH is not set) a suitable search path based on the settings in man.conf and the user's environment Searches the whatis database and displays the short descriptions of system commands that contain the given keyword as a separate word Reads files and replaces lines of the form .so file by the contents of the mentioned file

6.51.1. Installation of Module-Init-Tools
To avoid a problem with regenerating the man pages when not needed, first rewrite a file that just points to another man page: echo '.so man5/modprobe.conf.5' > modprobe.d.5 The test suite of this package is geared towards the needs of its Maintainer. The command make check builds a specially wrapped version of modprobe which is useless for normal operation. To run this (about 0.2 SBU), issue the following commands (note that the make clean command is required to clean up the source tree before recompiling for normal use): ./configure make check ./tests/runtests make clean Prepare Module-Init-Tools for compilation: ./configure --prefix=/ --enable-zlib-dynamic --mandir=/usr/share/man Compile the package: make Install the package: make INSTALL=install install
The meaning of the make parameter:

INSTALL=install Normally, make install will not install the binaries if they already exist. This option overrides that behavior by calling install instead of using the default wrapper script.

Short Descriptions
depmod insmod insmod.static Creates a dependency file based on the symbols it finds in the existing set of modules; this dependency file is used by modprobe to automatically load the required modules Installs a loadable module in the running kernel A statically compiled version of insmod 171

Linux From Scratch - Version 6.7 lsmod modinfo modprobe rmmod Lists currently loaded modules Examines an object file associated with a kernel module and displays any information that it can glean Uses a dependency file, created by depmod, to automatically load relevant modules Unloads modules from the running kernel

172

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6.52. Patch-2.6.1
The Patch package contains a program for modifying or creating files by applying a “patch” file typically created by the diff program. Approximate build time: Required disk space: less than 0.1 SBU 1.9 MB

6.52.1. Installation of Patch
Apply a patch to prevent the test suite from running a test that requires ed: patch -Np1 -i ../patch-2.6.1-test_fix-1.patch Prepare Patch for compilation: ./configure --prefix=/usr Compile the package: make To test the results, issue: make check Install the package: make install

6.52.2. Contents of Patch
Installed program: patch

Short Descriptions
patch Modifies files according to a patch file. A patch file is normally a difference listing created with the diff program. By applying these differences to the original files, patch creates the patched versions.

6.53.1. Installation of Psmisc
Fix a bug that prevents peekfd from being built on the x86_64 architecture: sed -i 's@#include <sys\/user.h>@#include <bits\/types.h>\n&@' configure Prepare Psmisc for compilation: ./configure --prefix=/usr Compile the package: make This package does not come with a test suite. Install the package: make install Finally, move the killall and fuser programs to the location specified by the FHS: mv -v /usr/bin/fuser /bin mv -v /usr/bin/killall /bin

Short Descriptions
fuser killall peekfd prtstat pstree pstree.x11 Reports the Process IDs (PIDs) of processes that use the given files or file systems Kills processes by name; it sends a signal to all processes running any of the given commands Peek at file descriptors of a running process, given its PID Prints information about a process Displays running processes as a tree Same as pstree, except that it waits for confirmation before exiting

6.54.1. Installation of Shadow
Note
If you would like to enforce the use of strong passwords, refer to http://www.linuxfromscratch. org/blfs/view/svn/postlfs/cracklib.html for installing CrackLib prior to building Shadow. Then add --with-libcrack to the configure command below. Disable the installation of the groups program and its man pages, as Coreutils provides a better version: sed -i 's/groups$(EXEEXT) //' src/Makefile.in find man -name Makefile.in -exec sed -i 's/groups\.1 / /' {} \; Disable the installation of Chinese and Korean manual pages, since Man-DB cannot format them properly: sed -i -e 's/ ko//' -e 's/ zh_CN zh_TW//' man/Makefile.in Instead of using the default crypt method, use the more secure MD5 method of password encryption, which also allows passwords longer than 8 characters. It is also necessary to change the obsolete /var/spool/mail location for user mailboxes that Shadow uses by default to the /var/mail location used currently: sed -i -e 's@#ENCRYPT_METHOD DES@ENCRYPT_METHOD MD5@' \ -e 's@/var/spool/mail@/var/mail@' etc/login.defs

Note
If you chose to build Shadow with Cracklib support, run the following: sed -i 's@DICTPATH.*@DICTPATH\t/lib/cracklib/pw_dict@' \ etc/login.defs Prepare Shadow for compilation: ./configure --sysconfdir=/etc Compile the package: make This package does not come with a test suite. Install the package: make install Move a misplaced program to its proper location: mv -v /usr/bin/passwd /bin 175

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6.54.2. Configuring Shadow
This package contains utilities to add, modify, and delete users and groups; set and change their passwords; and perform other administrative tasks. For a full explanation of what password shadowing means, see the doc/HOWTO file within the unpacked source tree. If using Shadow support, keep in mind that programs which need to verify passwords (display managers, FTP programs, pop3 daemons, etc.) must be Shadow-compliant. That is, they need to be able to work with shadowed passwords. To enable shadowed passwords, run the following command: pwconv To enable shadowed group passwords, run: grpconv Shadow's stock configuration for the useradd utility has a few caveats that need some explanation. First, the default action for the useradd utility is to create the user and a group of the same name as the user. By default the user ID (UID) and group ID (GID) numbers will begin with 1000. This means if you don't pass parameters to useradd, each user will be a member of a unique group on the system. If this behaviour is undesireable, you'll need to pass the -g parameter to useradd. The default parameters are stored in the /etc/default/useradd file. You may need to modify two parameters in this file to suit your particular needs.
/etc/default/useradd Parameter Explanations

GROUP=1000 This parameter sets the beginning of the group numbers used in the /etc/group file. You can modify it to anything you desire. Note that useradd will never reuse a UID or GID. If the number identified in this parameter is used, it will use the next available number after this. Note also that if you don't have a group 1000 on your system the first time you use useradd without the -g parameter, you'll get a message displayed on the terminal that says: useradd: unknown GID 1000. You may disregard this message and group number 1000 will be used. CREATE_MAIL_SPOOL=yes This parameter causes useradd to create a mailbox file for the newly created user. useradd will make the group ownership of this file to the mail group with 0660 permissions. If you would prefer that these mailbox files are not created by useradd, issue the following command: sed -i 's/yes/no/' /etc/default/useradd

6.54.3. Setting the root password
Choose a password for user root and set it by running: passwd root

Short Descriptions
chage chfn chgpasswd chpasswd chsh expiry faillog gpasswd groupadd groupdel groupmems groupmod grpck grpconv grpunconv lastlog login logoutd newgrp newusers nologin passwd pwck pwconv pwunconv sg su useradd userdel usermod vigr vipw Used to change the maximum number of days between obligatory password changes Used to change a user's full name and other information Used to update group passwords in batch mode Used to update user passwords in batch mode Used to change a user's default login shell Checks and enforces the current password expiration policy Is used to examine the log of login failures, to set a maximum number of failures before an account is blocked, or to reset the failure count Is used to add and delete members and administrators to groups Creates a group with the given name Deletes the group with the given name Allows a user to administer his/her own group membership list without the requirement of super user privileges. Is used to modify the given group's name or GID Verifies the integrity of the group files /etc/group and /etc/gshadow Creates or updates the shadow group file from the normal group file Updates /etc/group from /etc/gshadow and then deletes the latter Reports the most recent login of all users or of a given user Is used by the system to let users sign on Is a daemon used to enforce restrictions on log-on time and ports Is used to change the current GID during a login session Is used to create or update an entire series of user accounts Displays a message that an account is not available. Designed to be used as the default shell for accounts that have been disabled Is used to change the password for a user or group account Verifies the integrity of the password files /etc/passwd and /etc/shadow Creates or updates the shadow password file from the normal password file Updates /etc/passwd from /etc/shadow and then deletes the latter Executes a given command while the user's GID is set to that of the given group Runs a shell with substitute user and group IDs Creates a new user with the given name, or updates the default new-user information Deletes the given user account Is used to modify the given user's login name, User Identification (UID), shell, initial group, home directory, etc. Edits the /etc/group or /etc/gshadow files Edits the /etc/passwd or /etc/shadow files 177

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6.55. Sysklogd-1.5
The Sysklogd package contains programs for logging system messages, such as those given by the kernel when unusual things happen. Approximate build time: Required disk space: less than 0.1 SBU 0.5 MB

6.55.1. Installation of Sysklogd
Compile the package: make This package does not come with a test suite. Install the package: make BINDIR=/sbin install

Short Descriptions
klogd syslogd A system daemon for intercepting and logging kernel messages Logs the messages that system programs offer for logging. Every logged message contains at least a date stamp and a hostname, and normally the program's name too, but that depends on how trusting the logging daemon is told to be

6.56.1. Installation of Sysvinit
When run-levels are changed (for example, when halting the system), init sends termination signals to those processes that init itself started and that should not be running in the new run-level. While doing this, init outputs messages like “Sending processes the TERM signal” which seem to imply that it is sending these signals to all currently running processes. To avoid this misinterpretation, modify the source so that these messages read like “Sending processes configured via /etc/inittab the TERM signal” instead: sed -i 's@Sending processes@& configured via /etc/inittab@g' \ src/init.c A maintained version of the wall program was installed earlier by Util-linux-ng. Suppress the installation of Sysvinit's version of this program and its man page: sed -i -e 's/utmpdump wall/utmpdump/' \ -e 's/mountpoint.1 wall.1/mountpoint.1/' src/Makefile Compile the package: make -C src This package does not come with a test suite. Install the package: make -C src install

Short Descriptions
bootlogd fstab-decode halt Logs boot messages to a log file Run a command with fstab-encoded arguments Normally invokes shutdown with the -h option, except when already in run-level 0, then it tells the kernel to halt the system; it notes in the file /var/log/wtmp that the system is being brought down The first process to be started when the kernel has initialized the hardware which takes over the boot process and starts all the proceses it is instructed to 180

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Linux From Scratch - Version 6.7 killall5 last lastb mesg mountpoint pidof poweroff reboot runlevel shutdown sulogin telinit utmpdump Sends a signal to all processes, except the processes in its own session so it will not kill the shell running the script that called it Shows which users last logged in (and out), searching back through the /var/log/wtmp file; it also shows system boots, shutdowns, and run-level changes Shows the failed login attempts, as logged in /var/log/btmp Controls whether other users can send messages to the current user's terminal Checks if the directory is a mountpoint Reports the PIDs of the given programs Tells the kernel to halt the system and switch off the computer (see halt) Tells the kernel to reboot the system (see halt) Reports the previous and the current run-level, as noted in the last run-level record in /var/run/utmp Brings the system down in a secure way, signaling all processes and notifying all logged-in users Allows root to log in; it is normally invoked by init when the system goes into single user mode Tells init which run-level to change to Displays the content of the given login file in a more user-friendly format

6.57.1. Installation of Tar
Again, fix a bug that was inserted into the latest code release: sed -i /SIGPIPE/d src/tar.c Also, fix a bug that causes a buffer overflow when creating a new tar file. This fix is needed when building with gcc-4.5 and later. patch -Np1 -i ../tar-1.23-overflow_fix-1.patch Prepare Tar for compilation: ./configure --prefix=/usr --bindir=/bin --libexecdir=/usr/sbin Compile the package: make To test the results (about 1 SBU), issue: sed -i '35 i\ AT_UNPRIVILEGED_PREREQ' tests/remfiles01.at make check Install the package: make install

6.57.2. Contents of Tar
Installed programs: rmt and tar

Short Descriptions
rmt tar Remotely manipulates a magnetic tape drive through an interprocess communication connection Creates, extracts files from, and lists the contents of archives, also known as tarballs

6.58.1. Installation of Texinfo
Prepare Texinfo for compilation: ./configure --prefix=/usr Compile the package: make To test the results, issue: make check Install the package: make install Optionally, install the components belonging in a TeX installation: make TEXMF=/usr/share/texmf install-tex
The meaning of the make parameter:

TEXMF=/usr/share/texmf The TEXMF makefile variable holds the location of the root of the TeX tree if, for example, a TeX package will be installed later. The Info documentation system uses a plain text file to hold its list of menu entries. The file is located at /usr/share/info/dir. Unfortunately, due to occasional problems in the Makefiles of various packages, it can sometimes get out of sync with the info pages installed on the system. If the /usr/share/info/dir file ever needs to be recreated, the following optional commands will accomplish the task: cd /usr/share/info rm -v dir for f in * do install-info $f dir 2>/dev/null done

Short Descriptions
info Used to read info pages which are similar to man pages, but often go much deeper than just explaining all the available command line options. For example, compare man bison and info bison. 183

Linux From Scratch - Version 6.7 infokey install-info makeinfo pdftexi2dvi texi2dvi texi2pdf texindex Compiles a source file containing Info customizations into a binary format Used to install info pages; it updates entries in the info index file Translates the given Texinfo source documents into info pages, plain text, or HTML Used to format the given Texinfo document into a Portable Document Format (PDF) file Used to format the given Texinfo document into a device-independent file that can be printed Used to format the given Texinfo document into a Portable Document Format (PDF) file Used to sort Texinfo index files

6.59.1. Installation of Udev
The udev-config tarball contains LFS-specific files used to configure Udev. Unpack it into the Udev source directory: tar -xvf ../udev-config-20100128.tar.bz2 The udev-testfiles tarball contains files needed to test udev. The file expands to an apparant size of about 37MB but the actual disk usage is less than 7MB. tar -xvf ../udev-161-testfiles.tar.bz2 --strip-components=1 Create some devices and directories that Udev cannot handle due to them being required very early in the boot process, or by Udev itself: install -dv /lib/{firmware,udev/devices/{pts,shm}} mknod -m0666 /lib/udev/devices/null c 1 3 Prepare the package for compilation: ./configure --prefix=/usr \ --sysconfdir=/etc --sbindir=/sbin \ --with-rootlibdir=/lib --libexecdir=/lib/udev \ --disable-extras --disable-introspection
The meaning of the new configure options

--with-rootlibdir=/lib This controls where the libudev library is installed. The library needs to be in /lib because it's used by Udev at boot time, before /usr might be available, and the default --rootlibdir is /usr/lib. --libexecdir=/lib/udev This controls where Udev-internal rules and helper programs are installed. --disable-extras This option prevents Udev from installing helper programs and other extras which require more external libraries. These libraries are not part of the base LFS system. See the Udev README file for more information. --disable-introspection This option prevents Udev's instrospection feature, which requires packages not installed as part of the base LFS system. See the Udev README file for more information. Compile the package: make Test the package. make check 185

Short Descriptions
ata_id cdrom_id collect create_floppy_devices edd_id firmware.sh fstab_import path_id scsi_id udevadm Provides Udev with a unique string and additional information (uuid, label) for an ATA drive Provides Udev with the capabilities of a CD-ROM or DVD-ROM drive Given an ID for the current uevent and a list of IDs (for all target uevents), registers the current ID and indicates whether all target IDs have been registered Creates all possible floppy devices based on the CMOS type Provides Udev with the EDD ID for a BIOS disk drive Uploads firmware to devices Finds an entry in /etc/fstab that matches the current device, and provides its information to Udev Provides the shortest possible unique hardware path to a device Provides Udev with a unique SCSI identifier based on the data returned from sending a SCSI INQUIRY command to the specified device Generic udev administration tool: controls the udevd daemon, provides info from the Udev database, monitors uevents, waits for uevents to finish, tests Udev configuration, and triggers uevents for a given device A daemon that listens for uevents on the netlink socket, creates devices and runs the configured external programs in response to these uevents Provides Udev with information about USB devices A script which generates Udev rules to provide stable names for optical drives (see also Section 7.10, “Creating Custom Symlinks to Devices”) 186

Alternatives to Vim
If you prefer another editor—such as Emacs, Joe, or Nano—please refer to http://www.linuxfromscratch. org/blfs/view/svn/postlfs/editors.html for suggested installation instructions.

--enable-multibyte This switch enables support for editing files in multibyte character encodings. This is needed if using a locale with a multibyte character set. This switch is also helpful to be able to edit text files initially created in Linux distributions like Fedora that use UTF-8 as a default character set. Compile the package: make To test the results, issue: make test However, this test suite outputs a lot of binary data to the screen, which can cause issues with the settings of the current terminal. This can be resolved by redirecting the output to a log file. Install the package: make install Many users are used to using vi instead of vim. To allow execution of vim when users habitually enter vi, create a symlink for both the binary and the man page in the provided languages: ln -sv vim /usr/bin/vi for L in /usr/share/man/{,*/}man1/vim.1; do ln -sv vim.1 $(dirname $L)/vi.1 done By default, Vim's documentation is installed in /usr/share/vim. The following symlink allows the documentation to be accessed via /usr/share/doc/vim-7.3, making it consistent with the location of documentation for other packages: ln -sv ../vim/vim73/doc /usr/share/doc/vim-7.3 188

Linux From Scratch - Version 6.7 If an X Window System is going to be installed on the LFS system, it may be necessary to recompile Vim after installing X. Vim comes with a GUI version of the editor that requires X and some additional libraries to be installed. For more information on this process, refer to the Vim documentation and the Vim installation page in the BLFS book at http://www.linuxfromscratch.org/blfs/view/svn/postlfs/editors.html#postlfs-editors-vim.

6.60.2. Configuring Vim
By default, vim runs in vi-incompatible mode. This may be new to users who have used other editors in the past. The “nocompatible” setting is included below to highlight the fact that a new behavior is being used. It also reminds those who would change to “compatible” mode that it should be the first setting in the configuration file. This is necessary because it changes other settings, and overrides must come after this setting. Create a default vim configuration file by running the following: cat > /etc/vimrc << "EOF" " Begin /etc/vimrc set nocompatible set backspace=2 syntax on if (&term == "iterm") || (&term == "putty") set background=dark endif " End /etc/vimrc EOF The set nocompatible setting makes vim behave in a more useful way (the default) than the vi-compatible manner. Remove the “no” to keep the old vi behavior. The set backspace=2 setting allows backspacing over line breaks, autoindents, and the start of insert. The syntax on parameter enables vim's syntax highlighting. Finally, the if statement with the set background=dark setting corrects vim's guess about the background color of some terminal emulators. This gives the highlighting a better color scheme for use on the black background of these programs. Documentation for other available options can be obtained by running the following command: vim -c ':options'

Note
By default, Vim only installs spell files for the English language. To install spell files for your preferred language, download the *.spl and optionally, the *.sug files for your language and character encoding from ftp://ftp.vim.org/pub/vim/runtime/spell/ and save them to /usr/share/vim/vim73/spell/. To use these spell files, some configuration in /etc/vimrc is needed, e.g.: set spelllang=en,ru set spell For more information, see the appropriate README file located at the URL above. 189

Short Descriptions
ex rview rvim vi view vim vimdiff vimtutor xxd Starts vim in ex mode Is a restricted version of view; no shell commands can be started and view cannot be suspended Is a restricted version of vim; no shell commands can be started and vim cannot be suspended Link to vim Starts vim in read-only mode Is the editor Edits two or three versions of a file with vim and show differences Teaches the basic keys and commands of vim Creates a hex dump of the given file; it can also do the reverse, so it can be used for binary patching

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6.61. About Debugging Symbols
Most programs and libraries are, by default, compiled with debugging symbols included (with gcc's -g option). This means that when debugging a program or library that was compiled with debugging information included, the debugger can provide not only memory addresses, but also the names of the routines and variables. However, the inclusion of these debugging symbols enlarges a program or library significantly. The following is an example of the amount of space these symbols occupy: • A bash binary with debugging symbols: 1200 KB • A bash binary without debugging symbols: 480 KB • Glibc and GCC files (/lib and /usr/lib) with debugging symbols: 87 MB • Glibc and GCC files without debugging symbols: 16 MB Sizes may vary depending on which compiler and C library were used, but when comparing programs with and without debugging symbols, the difference will usually be a factor between two and five. Because most users will never use a debugger on their system software, a lot of disk space can be regained by removing these symbols. The next section shows how to strip all debugging symbols from the programs and libraries.

6.62. Stripping Again
If the intended user is not a programmer and does not plan to do any debugging on the system software, the system size can be decreased by about 90 MB by removing the debugging symbols from binaries and libraries. This causes no inconvenience other than not being able to debug the software fully anymore. Most people who use the command mentioned below do not experience any difficulties. However, it is easy to make a typo and render the new system unusable, so before running the strip command, it is a good idea to make a backup of the LFS system in its current state. Before performing the stripping, take special care to ensure that none of the binaries that are about to be stripped are running. If unsure whether the user entered chroot with the command given in Section 6.4, “Entering the Chroot Environment,” first exit from chroot: logout Then reenter it with: chroot $LFS /tools/bin/env -i \ HOME=/root TERM=$TERM PS1='\u:\w\$ ' \ PATH=/bin:/usr/bin:/sbin:/usr/sbin \ /tools/bin/bash --login Now the binaries and libraries can be safely stripped: /tools/bin/find /{,usr/}{bin,lib,sbin} -type f \ -exec /tools/bin/strip --strip-debug '{}' ';' A large number of files will be reported as having their file format not recognized. These warnings can be safely ignored. These warnings indicate that those files are scripts instead of binaries. If disk space is very tight, the --strip-all option can be used on the binaries in /{,usr/}{bin,sbin} to gain several more megabytes. Do not use this option on libraries—they will be destroyed. 191

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6.63. Cleaning Up
From now on, when reentering the chroot environment after exiting, use the following modified chroot command: chroot "$LFS" /usr/bin/env -i \ HOME=/root TERM="$TERM" PS1='\u:\w\$ ' \ PATH=/bin:/usr/bin:/sbin:/usr/sbin \ /bin/bash --login The reason for this is that the programs in /tools are no longer needed. Since they are no longer needed you can delete the /tools directory if so desired.

Note
Removing /tools will also remove the temporary copies of Tcl, Expect, and DejaGNU which were used for running the toolchain tests. If you need these programs later on, they will need to be recompiled and re-installed. The BLFS book has instructions for this (see http://www.linuxfromscratch.org/blfs/). If the virtual kernel file systems have been unmounted, either manually or through a reboot, ensure that the virtual kernel file systems are mounted when reentering the chroot. This process was explained in Section 6.2.2, “Mounting and Populating /dev” and Section 6.2.3, “Mounting Virtual Kernel File Systems”.

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Chapter 7. Setting Up System Bootscripts
7.1. Introduction
This chapter details how to install and configure the LFS-Bootscripts package. Most of these scripts will work without modification, but a few require additional configuration files because they deal with hardware-dependent information. System-V style init scripts are employed in this book because they are widely used. For additional options, a hint detailing the BSD style init setup is available at http://www.linuxfromscratch.org/hints/downloads/files/bsd-init.txt. Searching the LFS mailing lists for “depinit” will also offer additional choices. If using an alternative style of init scripts, skip this chapter and move on to Chapter 8.

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7.2. LFS-Bootscripts-20100627
The LFS-Bootscripts package contains a set of scripts to start/stop the LFS system at bootup/shutdown. Approximate build time: Required disk space: less than 0.1 SBU 468 KB

7.2.1. Installation of LFS-Bootscripts
Install the package: make install

Short Descriptions
checkfs cleanfs Checks the integrity of the file systems before they are mounted (with the exception of journal and network based file systems) Removes files that should not be preserved between reboots, such as those in /var/run/ and /var/lock/; it re-creates /var/run/utmp and removes the possibly present /etc/nologin, /fastboot, and /forcefsck files Loads the correct keymap table for the desired keyboard layout; it also sets the screen font Sets the kernel log level to control messages reaching the console. Contains common functions, such as error and status checking, that are used by several bootscripts Halts the system Assists the network script with stopping network devices Assists the network script with starting network devices Sets up the system's hostname and local loopback device Loads kernel modules listed in /etc/sysconfig/modules, using arguments that are also given there Mounts all file systems, except ones that are marked noauto or are network based Mounts virtual kernel file systems, such as proc Sets up network interfaces, such as network cards, and sets up the default gateway (where applicable) The master run-level control script; it is responsible for running all the other bootscripts one-by-one, in a sequence determined by the name of the symbolic links being processed Reboots the system Makes sure every process is terminated before the system reboots or halts Resets the kernel clock to local time in case the hardware clock is not set to UTC time 194

Linux From Scratch - Version 6.7 static swap sysctl sysklogd template udev udev_retry Provides the functionality needed to assign a static Internet Protocol (IP) address to a network interface Enables and disables swap files and partitions Loads system configuration values from /etc/sysctl.conf, if that file exists, into the running kernel Starts and stops the system and kernel log daemons A template to create custom bootscripts for other daemons Prepares the /dev directory and starts Udev Retries failed udev uevents, and copies generated rules files from /dev/.udev to /etc/udev/rules.d if required

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7.3. How Do These Bootscripts Work?
Linux uses a special booting facility named SysVinit that is based on a concept of run-levels. It can be quite different from one system to another, so it cannot be assumed that because things worked in one particular Linux distribution, they should work the same in LFS too. LFS has its own way of doing things, but it respects generally accepted standards. SysVinit (which will be referred to as “init” from now on) works using a run-levels scheme. There are seven (numbered 0 to 6) run-levels (actually, there are more run-levels, but they are for special cases and are generally not used. See init(8) for more details), and each one of those corresponds to the actions the computer is supposed to perform when it starts up. The default run-level is 3. Here are the descriptions of the different run-levels as they are implemented: 0: halt the computer 1: single-user mode 2: multi-user mode without networking 3: multi-user mode with networking 4: reserved for customization, otherwise does the same as 3 5: same as 4, it is usually used for GUI login (like X's xdm or KDE's kdm) 6: reboot the computer The command used to change run-levels is init <runlevel>, where <runlevel> is the target run-level. For example, to reboot the computer, a user could issue the init 6 command, which is an alias for the reboot command. Likewise, init 0 is an alias for the halt command. There are a number of directories under /etc/rc.d that look like rc?.d (where ? is the number of the run-level) and rcsysinit.d, all containing a number of symbolic links. Some begin with a K, the others begin with an S, and all of them have two numbers following the initial letter. The K means to stop (kill) a service and the S means to start a service. The numbers determine the order in which the scripts are run, from 00 to 99—the lower the number the earlier it gets executed. When init switches to another run-level, the appropriate services are either started or stopped, depending on the runlevel chosen. The real scripts are in /etc/rc.d/init.d. They do the actual work, and the symlinks all point to them. Killing links and starting links point to the same script in /etc/rc.d/init.d. This is because the scripts can be called with different parameters like start, stop, restart, reload, and status. When a K link is encountered, the appropriate script is run with the stop argument. When an S link is encountered, the appropriate script is run with the start argument. There is one exception to this explanation. Links that start with an S in the rc0.d and rc6.d directories will not cause anything to be started. They will be called with the parameter stop to stop something. The logic behind this is that when a user is going to reboot or halt the system, nothing needs to be started. The system only needs to be stopped. These are descriptions of what the arguments make the scripts do: start The service is started. stop The service is stopped. restart The service is stopped and then started again. 196

Linux From Scratch - Version 6.7 reload The configuration of the service is updated. This is used after the configuration file of a service was modified, when the service does not need to be restarted. status Tells if the service is running and with which PIDs. Feel free to modify the way the boot process works (after all, it is your own LFS system). The files given here are an example of how it can be done.

7.4. Configuring the setclock Script
The setclock script reads the time from the hardware clock, also known as the BIOS or the Complementary Metal Oxide Semiconductor (CMOS) clock. If the hardware clock is set to UTC, this script will convert the hardware clock's time to the local time using the /etc/localtime file (which tells the hwclock program which timezone the user is in). There is no way to detect whether or not the hardware clock is set to UTC, so this needs to be configured manually. The setclock is run via udev when the kernel detects the hardware capability upon boot. It can also be run manually with the stop parameter to store the system time to the CMOS clock. If you cannot remember whether or not the hardware clock is set to UTC, find out by running the hwclock --localtime --show command. This will display what the current time is according to the hardware clock. If this time matches whatever your watch says, then the hardware clock is set to local time. If the output from hwclock is not local time, chances are it is set to UTC time. Verify this by adding or subtracting the proper amount of hours for the timezone to the time shown by hwclock. For example, if you are currently in the MST timezone, which is also known as GMT -0700, add seven hours to the local time. Change the value of the UTC variable below to a value of 0 (zero) if the hardware clock is not set to UTC time. Create a new file /etc/sysconfig/clock by running the following: cat > /etc/sysconfig/clock << "EOF" # Begin /etc/sysconfig/clock UTC=1 # Set this to any options you might need to give to hwclock, # such as machine hardware clock type for Alphas. CLOCKPARAMS= # End /etc/sysconfig/clock EOF A good hint explaining how to deal with time on LFS is available at http://www.linuxfromscratch. org/hints/downloads/files/time.txt. It explains issues such as time zones, UTC, and the TZ environment variable.

7.5. Configuring the Linux Console
This section discusses how to configure the console and consolelog bootscripts that set up the keyboard map, console font and console kernel log level. If non-ASCII characters (e.g., the copyright sign, the British pound sign and Euro symbol) will not be used and the keyboard is a U.S. one, much of this section can be skipped. Without the configuration file, the console bootscript will do nothing. 197

Linux From Scratch - Version 6.7 The console and consolelog script reads the /etc/sysconfig/console file for configuration information. Decide which keymap and screen font will be used. Various language-specific HOWTOs can also help with this, see http://www.tldp.org/HOWTO/HOWTO-INDEX/other-lang.html. If still in doubt, look in the /lib/kbd directory for valid keymaps and screen fonts. Read loadkeys(1) and setfont(8) manual pages to determine the correct arguments for these programs. The /etc/sysconfig/console file should contain lines of the form: VARIABLE="value". The following variables are recognized: LOGLEVEL This variable specifies the log level for kernel messages sent to the console as set by dmesg. Valid levels are from "1" (no messages) to "8". The default level is "7". KEYMAP This variable specifies the arguments for the loadkeys program, typically, the name of keymap to load, e.g., “es”. If this variable is not set, the bootscript will not run the loadkeys program, and the default kernel keymap will be used. KEYMAP_CORRECTIONS This (rarely used) variable specifies the arguments for the second call to the loadkeys program. This is useful if the stock keymap is not completely satisfactory and a small adjustment has to be made. E.g., to include the Euro sign into a keymap that normally doesn't have it, set this variable to “euro2”. FONT This variable specifies the arguments for the setfont program. Typically, this includes the font name, “-m”, and the name of the application character map to load. E.g., in order to load the “lat1-16” font together with the “8859-1” application character map (as it is appropriate in the USA), set this variable to “lat1-16 -m 8859-1”. In UTF-8 mode, the kernel uses the application character map for conversion of composed 8-bit key codes in the keymap to UTF-8, and thus the argument of the "-m" parameter should be set to the encoding of the composed key codes in the keymap. UNICODE Set this variable to “1”, “yes” or “true” in order to put the console into UTF-8 mode. This is useful in UTF-8 based locales and harmful otherwise. LEGACY_CHARSET For many keyboard layouts, there is no stock Unicode keymap in the Kbd package. The console bootscript will convert an available keymap to UTF-8 on the fly if this variable is set to the encoding of the available non-UTF-8 keymap. Some examples: • For a non-Unicode setup, only the KEYMAP and FONT variables are generally needed. E.g., for a Polish setup, one would use: cat > /etc/sysconfig/console << "EOF" # Begin /etc/sysconfig/console KEYMAP="pl2" FONT="lat2a-16 -m 8859-2" # End /etc/sysconfig/console EOF 198

Linux From Scratch - Version 6.7 • As mentioned above, it is sometimes necessary to adjust a stock keymap slightly. The following example adds the Euro symbol to the German keymap: cat > /etc/sysconfig/console << "EOF" # Begin /etc/sysconfig/console KEYMAP="de-latin1" KEYMAP_CORRECTIONS="euro2" FONT="lat0-16 -m 8859-15" # End /etc/sysconfig/console EOF • The following is a Unicode-enabled example for Bulgarian, where a stock UTF-8 keymap exists: cat > /etc/sysconfig/console << "EOF" # Begin /etc/sysconfig/console UNICODE="1" KEYMAP="bg_bds-utf8" FONT="LatArCyrHeb-16" # End /etc/sysconfig/console EOF • Due to the use of a 512-glyph LatArCyrHeb-16 font in the previous example, bright colors are no longer available on the Linux console unless a framebuffer is used. If one wants to have bright colors without framebuffer and can live without characters not belonging to his language, it is still possible to use a language-specific 256-glyph font, as illustrated below: cat > /etc/sysconfig/console << "EOF" # Begin /etc/sysconfig/console UNICODE="1" KEYMAP="bg_bds-utf8" FONT="cyr-sun16" # End /etc/sysconfig/console EOF

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Linux From Scratch - Version 6.7 • The following example illustrates keymap autoconversion from ISO-8859-15 to UTF-8 and enabling dead keys in Unicode mode: cat > /etc/sysconfig/console << "EOF" # Begin /etc/sysconfig/console UNICODE="1" KEYMAP="de-latin1" KEYMAP_CORRECTIONS="euro2" LEGACY_CHARSET="iso-8859-15" FONT="LatArCyrHeb-16 -m 8859-15" # End /etc/sysconfig/console EOF • Some keymaps have dead keys (i.e., keys that don't produce a character by themselves, but put an accent on the character produced by the next key) or define composition rules (such as: “press Ctrl+. A E to get Æ” in the default keymap). Linux-2.6.35.4 interprets dead keys and composition rules in the keymap correctly only when the source characters to be composed together are not multibyte. This deficiency doesn't affect keymaps for European languages, because there accents are added to unaccented ASCII characters, or two ASCII characters are composed together. However, in UTF-8 mode it is a problem, e.g., for the Greek language, where one sometimes needs to put an accent on the letter “alpha”. The solution is either to avoid the use of UTF-8, or to install the X window system that doesn't have this limitation in its input handling. • For Chinese, Japanese, Korean and some other languages, the Linux console cannot be configured to display the needed characters. Users who need such languages should install the X Window System, fonts that cover the necessary character ranges, and the proper input method (e.g., SCIM, it supports a wide variety of languages).

Note
The /etc/sysconfig/console file only controls the Linux text console localization. It has nothing to do with setting the proper keyboard layout and terminal fonts in the X Window System, with ssh sessions or with a serial console. In such situations, limitations mentioned in the last two list items above do not apply.

7.6. Configuring the sysklogd Script
The sysklogd script invokes the syslogd program with the -m 0 option. This option turns off the periodic timestamp mark that syslogd writes to the log files every 20 minutes by default. If you want to turn on this periodic timestamp mark, edit the sysklogd script and make the changes accordingly. See man syslogd for more information.

7.7. Creating the /etc/inputrc File
The inputrc file handles keyboard mapping for specific situations. This file is the startup file used by Readline — the input-related library — used by Bash and most other shells. Most people do not need user-specific keyboard mappings so the command below creates a global /etc/inputrc used by everyone who logs in. If you later decide you need to override the defaults on a per-user basis, you can create a .inputrc file in the user's home directory with the modified mappings. 200

Linux From Scratch - Version 6.7 For more information on how to edit the inputrc file, see info bash under the Readline Init File section. info readline is also a good source of information.

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Linux From Scratch - Version 6.7 Below is a generic global inputrc along with comments to explain what the various options do. Note that comments cannot be on the same line as commands. Create the file using the following command: cat > /etc/inputrc << "EOF" # Begin /etc/inputrc # Modified by Chris Lynn <roryo@roryo.dynup.net> # Allow the command prompt to wrap to the next line set horizontal-scroll-mode Off # Enable 8bit input set meta-flag On set input-meta On # Turns off 8th bit stripping set convert-meta Off # Keep the 8th bit for display set output-meta On # none, visible or audible set bell-style none # All of the following map the escape sequence of the value # contained in the 1st argument to the readline specific functions "\eOd": backward-word "\eOc": forward-word # for linux console "\e[1~": beginning-of-line "\e[4~": end-of-line "\e[5~": beginning-of-history "\e[6~": end-of-history "\e[3~": delete-char "\e[2~": quoted-insert # for xterm "\eOH": beginning-of-line "\eOF": end-of-line # for Konsole "\e[H": beginning-of-line "\e[F": end-of-line # End /etc/inputrc EOF

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7.8. The Bash Shell Startup Files
The shell program /bin/bash (hereafter referred to as “the shell”) uses a collection of startup files to help create an environment to run in. Each file has a specific use and may affect login and interactive environments differently. The files in the /etc directory provide global settings. If an equivalent file exists in the home directory, it may override the global settings. An interactive login shell is started after a successful login, using /bin/login, by reading the /etc/passwd file. An interactive non-login shell is started at the command-line (e.g., [prompt]$/bin/bash). A non-interactive shell is usually present when a shell script is running. It is non-interactive because it is processing a script and not waiting for user input between commands. For more information, see info bash under the Bash Startup Files and Interactive Shells section. The files /etc/profile and ~/.bash_profile are read when the shell is invoked as an interactive login shell. The base /etc/profile below sets some environment variables necessary for native language support. Setting them properly results in: • The output of programs translated into the native language • Correct classification of characters into letters, digits and other classes. This is necessary for bash to properly accept non-ASCII characters in command lines in non-English locales • The correct alphabetical sorting order for the country • Appropriate default paper size • Correct formatting of monetary, time, and date values Replace <ll> below with the two-letter code for the desired language (e.g., “en”) and <CC> with the two-letter code for the appropriate country (e.g., “GB”). <charmap> should be replaced with the canonical charmap for your chosen locale. Optional modifiers such as “@euro” may also be present. The list of all locales supported by Glibc can be obtained by running the following command: locale -a Charmaps can have a number of aliases, e.g., “ISO-8859-1” is also referred to as “iso8859-1” and “iso88591”. Some applications cannot handle the various synonyms correctly (e.g., require that “UTF-8” is written as “UTF-8”, not “utf8”), so it is safest in most cases to choose the canonical name for a particular locale. To determine the canonical name, run the following command, where <locale name> is the output given by locale -a for your preferred locale (“en_GB.iso88591” in our example). LC_ALL=<locale name> locale charmap For the “en_GB.iso88591” locale, the above command will print: ISO-8859-1 This results in a final locale setting of “en_GB.ISO-8859-1”. It is important that the locale found using the heuristic above is tested prior to it being added to the Bash startup files: LC_ALL=<locale LC_ALL=<locale LC_ALL=<locale LC_ALL=<locale name> name> name> name> locale locale locale locale language charmap int_curr_symbol int_prefix 203

Linux From Scratch - Version 6.7 The above commands should print the language name, the character encoding used by the locale, the local currency, and the prefix to dial before the telephone number in order to get into the country. If any of the commands above fail with a message similar to the one shown below, this means that your locale was either not installed in Chapter 6 or is not supported by the default installation of Glibc. locale: Cannot set LC_* to default locale: No such file or directory If this happens, you should either install the desired locale using the localedef command, or consider choosing a different locale. Further instructions assume that there are no such error messages from Glibc. Some packages beyond LFS may also lack support for your chosen locale. One example is the X library (part of the X Window System), which outputs the following error message if the locale does not exactly match one of the character map names in its internal files: Warning: locale not supported by Xlib, locale set to C In several cases Xlib expects that the character map will be listed in uppercase notation with canonical dashes. For instance, "ISO-8859-1" rather than "iso88591". It is also possible to find an appropriate specification by removing the charmap part of the locale specification. This can be checked by running the locale charmap command in both locales. For example, one would have to change "de_DE.ISO-8859-15@euro" to "de_DE@euro" in order to get this locale recognized by Xlib. Other packages can also function incorrectly (but may not necessarily display any error messages) if the locale name does not meet their expectations. In those cases, investigating how other Linux distributions support your locale might provide some useful information. Once the proper locale settings have been determined, create the /etc/profile file: cat > /etc/profile << "EOF" # Begin /etc/profile export LANG=<ll>_<CC>.<charmap><@modifiers> # End /etc/profile EOF The “C” (default) and “en_US” (the recommended one for United States English users) locales are different. “C” uses the US-ASCII 7-bit character set, and treats bytes with the high bit set as invalid characters. That's why, e.g., the ls command substitutes them with question marks in that locale. Also, an attempt to send mail with such characters from Mutt or Pine results in non-RFC-conforming messages being sent (the charset in the outgoing mail is indicated as “unknown 8-bit”). So you can use the “C” locale only if you are sure that you will never need 8-bit characters. UTF-8 based locales are not supported well by many programs. Work is in progress to document and, if possible, fix such problems, see http://www.linuxfromscratch.org/blfs/view/svn/introduction/locale-issues.html.

7.9. Device and Module Handling on an LFS System
In Chapter 6, we installed the Udev package. Before we go into the details regarding how this works, a brief history of previous methods of handling devices is in order. Linux systems in general traditionally use a static device creation method, whereby a great many device nodes are created under /dev (sometimes literally thousands of nodes), regardless of whether the corresponding hardware devices actually exist. This is typically done via a MAKEDEV script, which contains a number of calls to the mknod program with the relevant major and minor device numbers for every possible device that might exist in the world. 204

Linux From Scratch - Version 6.7 Using the Udev method, only those devices which are detected by the kernel get device nodes created for them. Because these device nodes will be created each time the system boots, they will be stored on a tmpfs file system (a virtual file system that resides entirely in system memory). Device nodes do not require much space, so the memory that is used is negligible.

7.9.1. History
In February 2000, a new filesystem called devfs was merged into the 2.3.46 kernel and was made available during the 2.4 series of stable kernels. Although it was present in the kernel source itself, this method of creating devices dynamically never received overwhelming support from the core kernel developers. The main problem with the approach adopted by devfs was the way it handled device detection, creation, and naming. The latter issue, that of device node naming, was perhaps the most critical. It is generally accepted that if device names are allowed to be configurable, then the device naming policy should be up to a system administrator, not imposed on them by any particular developer(s). The devfs file system also suffers from race conditions that are inherent in its design and cannot be fixed without a substantial revision to the kernel. It was marked as deprecated for a long period – due to a lack of maintenance – and was finally removed from the kernel in June, 2006. With the development of the unstable 2.5 kernel tree, later released as the 2.6 series of stable kernels, a new virtual filesystem called sysfs came to be. The job of sysfs is to export a view of the system's hardware configuration to userspace processes. With this userspace-visible representation, the possibility of seeing a userspace replacement for devfs became much more realistic.

7.9.2. Udev Implementation
7.9.2.1. Sysfs
The sysfs filesystem was mentioned briefly above. One may wonder how sysfs knows about the devices present on a system and what device numbers should be used for them. Drivers that have been compiled into the kernel directly register their objects with sysfs as they are detected by the kernel. For drivers compiled as modules, this registration will happen when the module is loaded. Once the sysfs filesystem is mounted (on /sys), data which the built-in drivers registered with sysfs are available to userspace processes and to udevd for device node creation.

7.9.2.2. Udev Bootscript
The S10udev initscript takes care of creating device nodes when Linux is booted. The script unsets the uevent handler from the default of /sbin/hotplug. This is done because the kernel no longer needs to call out to an external binary. Instead udevd will listen on a netlink socket for uevents that the kernel raises. Next, the bootscript copies any static device nodes that exist in /lib/udev/devices to /dev. This is necessary because some devices, directories, and symlinks are needed before the dynamic device handling processes are available during the early stages of booting a system, or are required by udevd itself. Creating static device nodes in /lib/udev/devices also provides an easy workaround for devices that are not supported by the dynamic device handling infrastructure. The bootscript then starts the Udev daemon, udevd, which will act on any uevents it receives. Finally, the bootscript forces the kernel to replay uevents for any devices that have already been registered and then waits for udevd to handle them.

7.9.2.3. Device Node Creation
To obtain the right major and minor number for a device, Udev relies on the information provided by sysfs in /sys. For example, /sys/class/tty/vcs/dev contains the string “7:0”. This string is used by udevd to create a device node with major number 7 and minor 0. The names and permissions of the nodes created under the 205

Linux From Scratch - Version 6.7 /dev directory are determined by rules specified in the files within the /etc/udev/rules.d/ directory. These are numbered in a similar fashion to the LFS-Bootscripts package. If udevd can't find a rule for the device it is creating, it will default permissions to 660 and ownership to root:root. Documentation on the syntax of the Udev rules configuration files are available in /usr/share/doc/udev-161/writing_udev_rules/index.html

7.9.2.4. Module Loading
Device drivers compiled as modules may have aliases built into them. Aliases are visible in the output of the modinfo program and are usually related to the bus-specific identifiers of devices supported by a module. For example, the snd-fm801 driver supports PCI devices with vendor ID 0x1319 and device ID 0x0801, and has an alias of “pci:v00001319d00000801sv*sd*bc04sc01i*”. For most devices, the bus driver exports the alias of the driver that would handle the device via sysfs. E.g., the /sys/bus/pci/devices/0000:00:0d.0/modalias file might contain the string “pci:v00001319d00000801sv00001319sd00001319bc04sc01i00”. The default rules provided with Udev will cause udevd to call out to /sbin/modprobe with the contents of the MODALIAS uevent environment variable (which should be the same as the contents of the modalias file in sysfs), thus loading all modules whose aliases match this string after wildcard expansion. In this example, this means that, in addition to snd-fm801, the obsolete (and unwanted) forte driver will be loaded if it is available. See below for ways in which the loading of unwanted drivers can be prevented. The kernel itself is also able to load modules for network protocols, filesystems and NLS support on demand.

7.9.2.5. Handling Hotpluggable/Dynamic Devices
When you plug in a device, such as a Universal Serial Bus (USB) MP3 player, the kernel recognizes that the device is now connected and generates a uevent. This uevent is then handled by udevd as described above.

7.9.3. Problems with Loading Modules and Creating Devices
There are a few possible problems when it comes to automatically creating device nodes.

7.9.3.1. A kernel module is not loaded automatically
Udev will only load a module if it has a bus-specific alias and the bus driver properly exports the necessary aliases to sysfs. In other cases, one should arrange module loading by other means. With Linux-2.6.35.4, Udev is known to load properly-written drivers for INPUT, IDE, PCI, USB, SCSI, SERIO and FireWire devices. To determine if the device driver you require has the necessary support for Udev, run modinfo with the module name as the argument. Now try locating the device directory under /sys/bus and check whether there is a modalias file there. If the modalias file exists in sysfs, the driver supports the device and can talk to it directly, but doesn't have the alias, it is a bug in the driver. Load the driver without the help from Udev and expect the issue to be fixed later. If there is no modalias file in the relevant directory under /sys/bus, this means that the kernel developers have not yet added modalias support to this bus type. With Linux-2.6.35.4, this is the case with ISA busses. Expect this issue to be fixed in later kernel versions. Udev is not intended to load “wrapper” drivers such as snd-pcm-oss and non-hardware drivers such as loop at all.

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7.9.3.2. A kernel module is not loaded automatically, and Udev is not intended to load it
If the “wrapper” module only enhances the functionality provided by some other module (e.g., snd-pcm-oss enhances the functionality of snd-pcm by making the sound cards available to OSS applications), configure modprobe to load the wrapper after Udev loads the wrapped module. To do this, add an “install” line in any /etc/modprobe. d/<filename>.conf file. For example: install snd-pcm /sbin/modprobe -i snd-pcm ; \ /sbin/modprobe snd-pcm-oss ; true If the module in question is not a wrapper and is useful by itself, configure the S05modules bootscript to load this module on system boot. To do this, add the module name to the /etc/sysconfig/modules file on a separate line. This works for wrapper modules too, but is suboptimal in that case.

7.9.3.3. Udev loads some unwanted module
Either don't build the module, or blacklist it in a /etc/modprobe.d/blacklist.conf file as done with the forte module in the example below: blacklist forte Blacklisted modules can still be loaded manually with the explicit modprobe command.

7.9.3.4. Udev creates a device incorrectly, or makes a wrong symlink
This usually happens if a rule unexpectedly matches a device. For example, a poorly-writen rule can match both a SCSI disk (as desired) and the corresponding SCSI generic device (incorrectly) by vendor. Find the offending rule and make it more specific, with the help of the udevadm info command.

7.9.3.5. Udev rule works unreliably
This may be another manifestation of the previous problem. If not, and your rule uses sysfs attributes, it may be a kernel timing issue, to be fixed in later kernels. For now, you can work around it by creating a rule that waits for the used sysfs attribute and appending it to the /etc/udev/rules.d/10-wait_for_sysfs.rules file (create this file if it does not exist). Please notify the LFS Development list if you do so and it helps.

7.9.3.6. Udev does not create a device
Further text assumes that the driver is built statically into the kernel or already loaded as a module, and that you have already checked that Udev doesn't create a misnamed device. Udev has no information needed to create a device node if a kernel driver does not export its data to sysfs. This is most common with third party drivers from outside the kernel tree. Create a static device node in /lib/udev/devices with the appropriate major/minor numbers (see the file devices.txt inside the kernel documentation or the documentation provided by the third party driver vendor). The static device node will be copied to /dev by the S10udev bootscript.

7.9.3.7. Device naming order changes randomly after rebooting
This is due to the fact that Udev, by design, handles uevents and loads modules in parallel, and thus in an unpredictable order. This will never be “fixed”. You should not rely upon the kernel device names being stable. Instead, create your own rules that make symlinks with stable names based on some stable attributes of the device, such as a serial number or the output of various *_id utilities installed by Udev. See Section 7.10, “Creating Custom Symlinks to Devices” and Section 7.13, “Configuring the network Script” for examples. 207

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7.9.4. Useful Reading
Additional helpful documentation is available at the following sites: • A Userspace Implementation of devfs http://www.kroah.com/linux/talks/ols_2003_udev_paper/Reprint-KroahHartman-OLS2003.pdf • The sysfs Filesystem http://www.kernel.org/pub/linux/kernel/people/mochel/doc/papers/ols-2005/mochel.pdf • Pointers to further reading http://www.kernel.org/pub/linux/utils/kernel/hotplug/udev.html

7.10. Creating Custom Symlinks to Devices
7.10.1. CD-ROM symlinks
Some software that you may want to install later (e.g., various media players) expect the /dev/cdrom and /dev/dvd symlinks to exist, and to point to a CD-ROM or DVD-ROM device. Also, it may be convenient to put references to those symlinks into /etc/fstab. Udev comes with a script that will generate rules files to create these symlinks for you, depending on the capabilities of each device, but you need to decide which of two modes of operation you wish to have the script use. First, the script can operate in “by-path” mode (used by default for USB and FireWire devices), where the rules it creates depend on the physical path to the CD or DVD device. Second, it can operate in “by-id” mode (default for IDE and SCSI devices), where the rules it creates depend on identification strings stored in the CD or DVD device itself. The path is determined by Udev's path_id script, and the identification strings are read from the hardware by its ata_id or scsi_id programs, depending on which type of device you have. There are advantages to each approach; the correct approach to use will depend on what kinds of device changes may happen. If you expect the physical path to the device (that is, the ports and/or slots that it plugs into) to change, for example because you plan on moving the drive to a different IDE port or a different USB connector, then you should use the “by-id” mode. On the other hand, if you expect the device's identification to change, for example because it may die, and you would replace it with a different device with the same capabilities and which is plugged into the same connectors, then you should use the “by-path” mode. If either type of change is possible with your drive, then choose a mode based on the type of change you expect to happen more often.

Important
External devices (for example, a USB-connected CD drive) should not use by-path persistence, because each time the device is plugged into a new external port, its physical path will change. All externally-connected devices will have this problem if you write Udev rules to recognize them by their physical path; the problem is not limited to CD and DVD drives. If you wish to see the values that the Udev scripts will use, then for the appropriate CD-ROM device, find the corresponding directory under /sys (e.g., this can be /sys/block/hdd) and run a command similar to the following: udevadm test /sys/block/hdd Look at the lines containing the output of various *_id programs. The “by-id” mode will use the ID_SERIAL value if it exists and is not empty, otherwise it will use a combination of ID_MODEL and ID_REVISION. The “by-path” mode will use the ID_PATH value. 208

Linux From Scratch - Version 6.7 If the default mode is not suitable for your situation, then the following modification can be made to the /lib/udev/rules.d/75-cd-aliases-generator.rules file, as follows (where mode is one of “by-id” or “by-path”): sed -i -e 's/write_cd_rules/& mode/' \ /lib/udev/rules.d/75-cd-aliases-generator.rules Note that it is not necessary to create the rules files or symlinks at this time, because you have bind-mounted the host's /dev directory into the LFS system, and we assume the symlinks exist on the host. The rules and symlinks will be created the first time you boot your LFS system. However, if you have multiple CD-ROM devices, then the symlinks generated at that time may point to different devices than they point to on your host, because devices are not discovered in a predictable order. The assignments created when you first boot the LFS system will be stable, so this is only an issue if you need the symlinks on both systems to point to the same device. If you need that, then inspect (and possibly edit) the generated /etc/udev/rules.d/70-persistent-cd.rules file after booting, to make sure the assigned symlinks match what you need.

7.10.2. Dealing with duplicate devices
As explained in Section 7.9, “Device and Module Handling on an LFS System”, the order in which devices with the same function appear in /dev is essentially random. E.g., if you have a USB web camera and a TV tuner, sometimes /dev/video0 refers to the camera and /dev/video1 refers to the tuner, and sometimes after a reboot the order changes to the opposite one. For all classes of hardware except sound cards and network cards, this is fixable by creating udev rules for custom persistent symlinks. The case of network cards is covered separately in Section 7.13, “Configuring the network Script”, and sound card configuration can be found in BLFS. For each of your devices that is likely to have this problem (even if the problem doesn't exist in your current Linux distribution), find the corresponding directory under /sys/class or /sys/block. For video devices, this may be /sys/class/video4linux/videoX. Figure out the attributes that identify the device uniquely (usually, vendor and product IDs and/or serial numbers work): udevadm info -a -p /sys/class/video4linux/video0 Then write rules that create the symlinks, e.g.: cat > /etc/udev/rules.d/83-duplicate_devs.rules << "EOF" # Persistent symlinks for webcam and tuner KERNEL=="video*", ATTRS{idProduct}=="1910", ATTRS{idVendor}=="0d81", \ SYMLINK+="webcam" KERNEL=="video*", ATTRS{device}=="0x036f", ATTRS{vendor}=="0x109e", \ SYMLINK+="tvtuner" EOF The result is that /dev/video0 and /dev/video1 devices still refer randomly to the tuner and the web camera (and thus should never be used directly), but there are symlinks /dev/tvtuner and /dev/webcam that always point to the correct device. 209

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7.11. Configuring the localnet Script
Part of the job of the localnet script is setting the system's hostname. This needs to be configured in the /etc/sysconfig/network file. Create the /etc/sysconfig/network file and enter a hostname by running: echo "HOSTNAME=<lfs>" > /etc/sysconfig/network <lfs> needs to be replaced with the name given to the computer. Do not enter the Fully Qualified Domain Name (FQDN) here. That information will be put in the /etc/hosts file in the next section.

7.12. Customizing the /etc/hosts File
If a network card is to be configured, decide on the IP address, fully-qualified domain name (FQDN), and possible aliases for use in the /etc/hosts file. The syntax is: IP_address myhost.example.org aliases Unless the computer is to be visible to the Internet (i.e., there is a registered domain and a valid block of assigned IP addresses—most users do not have this), make sure that the IP address is in the private network IP address range. Valid ranges are: Private Network Address Range 10.0.0.1 - 10.255.255.254 172.x.0.1 - 172.x.255.254 192.168.y.1 - 192.168.y.254 Normal Prefix 8 16 24

x can be any number in the range 16-31. y can be any number in the range 0-255. A valid private IP address could be 192.168.1.1. A valid FQDN for this IP could be lfs.example.org. Even if not using a network card, a valid FQDN is still required. This is necessary for certain programs to operate correctly. Create the /etc/hosts file by running: cat > /etc/hosts << "EOF" # Begin /etc/hosts (network card version) 127.0.0.1 localhost <192.168.1.1> <HOSTNAME.example.org> [alias1] [alias2 ...] # End /etc/hosts (network card version) EOF The <192.168.1.1> and <HOSTNAME.example.org> values need to be changed for specific users or requirements (if assigned an IP address by a network/system administrator and the machine will be connected to an existing network). The optional alias name(s) can be omitted. 210

7.13. Configuring the network Script
This section only applies if a network card is to be configured. If a network card will not be used, there is likely no need to create any configuration files relating to network cards. If that is the case, remove the network symlinks from all run-level directories (/etc/rc.d/rc*.d).

7.13.1. Creating stable names for network interfaces
With Udev and modular network drivers, the network interface numbering is not persistent across reboots by default, because the drivers are loaded in parallel and, thus, in random order. For example, on a computer having two network cards made by Intel and Realtek, the network card manufactured by Intel may become eth0 and the Realtek card becomes eth1. In some cases, after a reboot the cards get renumbered the other way around. To avoid this, Udev comes with a script and some rules to assign stable names to network cards based on their MAC address. Pre-generate the rules to ensure the same names get assigned to the same devices at every boot, including the first: for NIC in /sys/class/net/* ; do INTERFACE=${NIC##*/} udevadm test --action=add $NIC done Now, inspect the /etc/udev/rules.d/70-persistent-net.rules file, to find out which name was assigned to which network device: cat /etc/udev/rules.d/70-persistent-net.rules The file begins with a comment block followed by two lines for each NIC. The first line for each NIC is a commented description showing its hardware IDs (e.g. its PCI vendor and device IDs, if it's a PCI card), along with its driver in parentheses, if the driver can be found. Neither the hardware ID nor the driver is used to determine which name to give an interface; this information is only for reference. The second line is the Udev rule that matches this NIC and actually assigns it a name. All Udev rules are made up of several keys, separated by commas and optional whitespace. This rule's keys and an explanation of each of them are as follows: • SUBSYSTEM=="net" - This tells Udev to ignore devices that are not network cards. • ACTION=="add" - This tells Udev to ignore this rule for a uevent that isn't an add ("remove" and "change" uevents also happen, but don't need to rename network interfaces). • DRIVERS=="?*" - This exists so that Udev will ignore VLAN or bridge sub-interfaces (because these sub-interfaces do not have drivers). These sub-interfaces are skipped because the name that would be assigned would collide with their parent devices. 211

Linux From Scratch - Version 6.7 • ATTR{address} - The value of this key is the NIC's MAC address. • ATTR{type}=="1" - This ensures the rule only matches the primary interface in the case of certain wireless drivers, which create multiple virtual interfaces. The secondary interfaces are skipped for the same reason that VLAN and bridge sub-interfaces are skipped: there would be a name collision otherwise. • KERNEL=="eth*" - This key was added to the Udev rule generator to handle machines that have multiple network interfaces, all with the same MAC address (the PS3 is one such machine). If the independent interfaces have different basenames, this key will allow Udev to tell them apart. This is generally not necessary for most Linux From Scratch users, but does not hurt. • NAME - The value of this key is the name that Udev will assign to this interface. The value of NAME is the important part. Make sure you know which name has been assigned to each of your network cards before proceeding, and be sure to use that NAME value when creating your configuration files below.

7.13.2. Creating Network Interface Configuration Files
Which interfaces are brought up and down by the network script depends on the files and directories in the /etc/sysconfig/network-devices hierarchy. This directory should contain a sub-directory for each interface to be configured, such as ifconfig.xyz, where “xyz” is a network interface name. Inside this directory would be files defining the attributes to this interface, such as its IP address(es), subnet masks, and so forth. The following command creates a sample ipv4 file for the eth0 device: cd /etc/sysconfig/network-devices mkdir -v ifconfig.eth0 cat > ifconfig.eth0/ipv4 << "EOF" ONBOOT=yes SERVICE=ipv4-static IP=192.168.1.1 GATEWAY=192.168.1.2 PREFIX=24 BROADCAST=192.168.1.255 EOF The values of these variables must be changed in every file to match the proper setup. If the ONBOOT variable is set to “yes” the network script will bring up the Network Interface Card (NIC) during booting of the system. If set to anything but “yes” the NIC will be ignored by the network script and not be brought up. The SERVICE variable defines the method used for obtaining the IP address. The LFS-Bootscripts package has a modular IP assignment format, and creating additional files in the /etc/sysconfig/network-devices/services directory allows other IP assignment methods. This is commonly used for Dynamic Host Configuration Protocol (DHCP), which is addressed in the BLFS book. The GATEWAY variable should contain the default gateway IP address, if one is present. If not, then comment out the variable entirely. The PREFIX variable needs to contain the number of bits used in the subnet. Each octet in an IP address is 8 bits. If the subnet's netmask is 255.255.255.0, then it is using the first three octets (24 bits) to specify the network number. If the netmask is 255.255.255.240, it would be using the first 28 bits. Prefixes longer than 24 bits are commonly used by DSL and cable-based Internet Service Providers (ISPs). In this example (PREFIX=24), the netmask is 255.255.255.0. Adjust the PREFIX variable according to your specific subnet. 212

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7.13.3. Creating the /etc/resolv.conf File
If the system is going to be connected to the Internet, it will need some means of Domain Name Service (DNS) name resolution to resolve Internet domain names to IP addresses, and vice versa. This is best achieved by placing the IP address of the DNS server, available from the ISP or network administrator, into /etc/resolv.conf. Create the file by running the following: cat > /etc/resolv.conf << "EOF" # Begin /etc/resolv.conf domain <Your Domain Name> nameserver <IP address of your primary nameserver> nameserver <IP address of your secondary nameserver> # End /etc/resolv.conf EOF Replace <IP address of the nameserver> with the IP address of the DNS most appropriate for the setup. There will often be more than one entry (requirements demand secondary servers for fallback capability). If you only need or want one DNS server, remove the second nameserver line from the file. The IP address may also be a router on the local network.

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Chapter 8. Making the LFS System Bootable
8.1. Introduction
It is time to make the LFS system bootable. This chapter discusses creating an fstab file, building a kernel for the new LFS system, and installing the GRUB boot loader so that the LFS system can be selected for booting at startup.

8.2. Creating the /etc/fstab File
The /etc/fstab file is used by some programs to determine where file systems are to be mounted by default, in which order, and which must be checked (for integrity errors) prior to mounting. Create a new file systems table like this: cat > /etc/fstab << "EOF" # Begin /etc/fstab # file system # mount-point type options dump fsck order 1 0 0 0 0 0

Replace <xxx>, <yyy>, and <fff> with the values appropriate for the system, for example, hda2, hda5, and ext3. For details on the six fields in this file, see man 5 fstab. The /dev/shm mount point for tmpfs is included to allow enabling POSIX-shared memory. The kernel must have the required support built into it for this to work (more about this is in the next section). Please note that very little software currently uses POSIX-shared memory. Therefore, consider the /dev/shm mount point optional. For more information, see Documentation/filesystems/tmpfs.txt in the kernel source tree. Filesystems with MS-DOS or Windows origin (i.e.: vfat, ntfs, smbfs, cifs, iso9660, udf) need the “iocharset” mount option in order for non-ASCII characters in file names to be interpreted properly. The value of this option should be the same as the character set of your locale, adjusted in such a way that the kernel understands it. This works if the relevant character set definition (found under File systems -> Native Language Support) has been compiled into the kernel or built as a module. The “codepage” option is also needed for vfat and smbfs filesystems. It should be set to the codepage number used under MS-DOS in your country. E.g., in order to mount USB flash drives, a ru_RU.KOI8-R user would need the following in the options portion of its mount line in /etc/fstab: noauto,user,quiet,showexec,iocharset=koi8r,codepage=866 The corresponding options fragment for ru_RU.UTF-8 users is: noauto,user,quiet,showexec,iocharset=utf8,codepage=866 214

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Note
In the latter case, the kernel emits the following message: FAT: utf8 is not a recommended IO charset for FAT filesystems, filesystem will be case sensitive! This negative recommendation should be ignored, since all other values of the “iocharset” option result in wrong display of filenames in UTF-8 locales. It is also possible to specify default codepage and iocharset values for some filesystems during kernel configuration. The relevant parameters are named “Default NLS Option” (CONFIG_NLS_DEFAULT), “Default Remote NLS Option” (CONFIG_SMB_NLS_DEFAULT), “Default codepage for FAT” (CONFIG_FAT_DEFAULT_CODEPAGE), and “Default iocharset for FAT” (CONFIG_FAT_DEFAULT_IOCHARSET). There is no way to specify these settings for the ntfs filesystem at kernel compilation time. It is possible to make the ext3 filesystem reliable across power failures for some hard disk types. To do this, add the barrier=1 mount option to the appropriate entry in /etc/fstab. To check if the disk drive supports this option, run hdparm on the applicable disk drive. For example, if: hdparm -I /dev/sda | grep NCQ returns non-empty output, the option is supported. Note: Logical Volume Management (LVM) based partitions cannot use the barrier option.

8.3.1. Installation of the kernel
Building the kernel involves a few steps—configuration, compilation, and installation. Read the README file in the kernel source tree for alternative methods to the way this book configures the kernel. Prepare for compilation by running the following command: make mrproper This ensures that the kernel tree is absolutely clean. The kernel team recommends that this command be issued prior to each kernel compilation. Do not rely on the source tree being clean after un-tarring. Configure the kernel via a menu-driven interface. For general information on kernel configuration see http://www.linuxfromscratch.org/hints/downloads/files/kernel-configuration.txt. BLFS has some information regarding particular kernel configuration requirements of packages outside of LFS at http://www.linuxfromscratch. org/blfs/view/svn/longindex.html#kernel-config-index: make LANG=<host_LANG_value> LC_ALL= menuconfig
The meaning of the make parameters:

LANG=<host_LANG_value> LC_ALL= This establishes the locale setting to the one used on the host. This is needed for a proper menuconfig ncurses interface line drawing on UTF-8 linux text console. Be sure to replace <host_LANG_value> by the value of the $LANG variable from your host. If not set, you could use instead the host's value of $LC_ALL or $LC_CTYPE. Alternatively, make oldconfig may be more appropriate in some situations. See the README file for more information. If desired, skip kernel configuration by copying the kernel config file, .config, from the host system (assuming it is available) to the unpacked linux-2.6.35.4 directory. However, we do not recommend this option. It is often better to explore all the configuration menus and create the kernel configuration from scratch. Compile the kernel image and modules: make If using kernel modules, module configuration in /etc/modprobe.d may be required. Information pertaining to modules and kernel configuration is located in Section 7.9, “Device and Module Handling on an LFS System” and in the kernel documentation in the linux-2.6.35.4/Documentation directory. Also, modprobe.conf(5) may be of interest. Install the modules, if the kernel configuration uses them: make modules_install 216

Linux From Scratch - Version 6.7 After kernel compilation is complete, additional steps are required to complete the installation. Some files need to be copied to the /boot directory. The path to the kernel image may vary depending on the platform being used. The filename below can be changed to suit your taste, but the stem of the filename should be vmlinux to be compatible with the automatic setup of the boot process described in the next section. The following command assumes an x86 architecture: cp -v arch/x86/boot/bzImage /boot/vmlinux-2.6.35.4-lfs-6.7 System.map is a symbol file for the kernel. It maps the function entry points of every function in the kernel API, as well as the addresses of the kernel data structures for the running kernel. It is used as a resource when investigating kernel problems. Issue the following command to install the map file: cp -v System.map /boot/System.map-2.6.35.4 The kernel configuration file .config produced by the make menuconfig step above contains all the configuration selections for the kernel that was just compiled. It is a good idea to keep this file for future reference: cp -v .config /boot/config-2.6.35.4 Install the documentation for the Linux kernel: install -d /usr/share/doc/linux-2.6.35.4 cp -r Documentation/* /usr/share/doc/linux-2.6.35.4 It is important to note that the files in the kernel source directory are not owned by root. Whenever a package is unpacked as user root (like we did inside chroot), the files have the user and group IDs of whatever they were on the packager's computer. This is usually not a problem for any other package to be installed because the source tree is removed after the installation. However, the Linux source tree is often retained for a long time. Because of this, there is a chance that whatever user ID the packager used will be assigned to somebody on the machine. That person would then have write access to the kernel source. If the kernel source tree is going to be retained, run chown -R 0:0 on the linux-2.6.35.4 directory to ensure all files are owned by user root.

Warning
Some kernel documentation recommends creating a symlink from /usr/src/linux pointing to the kernel source directory. This is specific to kernels prior to the 2.6 series and must not be created on an LFS system as it can cause problems for packages you may wish to build once your base LFS system is complete.

Warning
The headers in the system's include directory should always be the ones against which Glibc was compiled, that is, the sanitised headers from this Linux kernel tarball. Therefore, they should never be replaced by either the raw kernel headers or any other kernel sanitized headers.

8.3.2. Configuring Linux Module Load Order
The /etc/modprobe.d/usb.conf file needs to be created so that if the USB drivers (ehci_hcd, ohci_hcd and uhci_hcd) have been built as modules, they will be loaded in the correct order; ehci_hcd needs to be loaded prior to ohci_hcd and uhci_hcd in order to avoid a warning being output at boot time. 217

Short Descriptions
config-2.6.35.4 vmlinux-2.6.35.4-lfs-6.7 Contains all the configuration selections for the kernel The engine of the Linux system. When turning on the computer, the kernel is the first part of the operating system that gets loaded. It detects and initializes all components of the computer's hardware, then makes these components available as a tree of files to the software and turns a single CPU into a multitasking machine capable of running scores of programs seemingly at the same time A list of addresses and symbols; it maps the entry points and addresses of all the functions and data structures in the kernel

System.map-2.6.35.4

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8.4. Using GRUB to Set Up the Boot Process
8.4.1. Introduction
Boot loading can be a complex area, so a few cautionary words are in order. Be familiar with the current boot loader and any other operating systems present on the hard drive(s) that need to be bootable. Make sure that an emergency boot disk is ready to “rescue” the computer if the computer becomes unusable (un-bootable). The procedure involves writing some special GRUB files to specific locations on the hard drive. We highly recommend creating a GRUB boot floppy diskette as a backup. Insert a blank floppy diskette and run the following commands: cd /tmp grub-mkrescue --output=grub-img.iso dd if=grub-img.iso of=/dev/fd0 bs=1440 count=1 Alternatively, a boot CD can be created by using your host system's CD burning tools to burn the grub-img.iso on to a blank CD. GRUB uses its own naming structure for drives and partitions in the form of (hdn,m), where n is the hard drive number and m is the partition number. The hard drive number starts from zero, but the partition number starts from one for normal partitions and five for extended partitions. Note that this is different from earlier versions where both numbers started from zero. For example, partition sda1 is (hd0,1) to GRUB and sdb3 is (hd1,3). In contrast to Linux, GRUB does not consider CD-ROM drives to be hard drives. For example, if using a CD on hdb and a second hard drive on hdc, that second hard drive would still be (hd1). You can determine what GRUB thinks your disk devices are by running: grub-mkdevicemap --device-map=device.map cat device.map The location of the boot partition is a choice of the user that affects the configuration. One recommendation is to have a separate small (suggested size is 100 MB) partition just for boot information. That way each build, whether LFS or some commercial distro, can access the same boot files and access can be made from any booted system. If you choose to do this, you will need to mount the separate partition, move all files in the current /boot directory (e.g. the linux kernel you just built in the previous section) to the new partition. You will then need to unmount the partition and remount it as /boot. If you do this, be sure to update /etc/fstab. Using the current lfs partition will also work, but configuration for multiple systems is more difficult.

8.4.2. Setting Up the Configuration
Using the above information, determine the appropriate designator for the root partition (or boot partition, if a separate one is used). For the following example, it is assumed that the root (or separate boot) partition is sda2. Install the GRUB files into /boot/grub: grub-install --grub-setup=/bin/true /dev/sda We use --grub-setup=/bin/true for now to prevent updating the Master Boot Record (MBR). In this way, we can test our installation before committing to a change that is hard to revert. 219

Linux From Scratch - Version 6.7 Generate /boot/grub/grub.cfg: grub-mkconfig -o /boot/grub/grub.cfg Here grub-mkconfig uses the files in /etc/grub.d/ to determine the contents of this file. The configuration file will look something like:
# # DO NOT EDIT THIS FILE # # It is automatically generated by /usr/sbin/grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### set set ### BEGIN /etc/grub.d/00_header ### default=0 timeout=5 END /etc/grub.d/00_header ###

Note
• Even though there is a warning not to edit the file, you can do so as long as you do not re-run grub-mkconfig. • The search lines are generally not useful for LFS systems as that command only sets an internal GRUB variable used to find the kernel image. The set root command provides the same capability without the overhead of searching. • The set root and insmod ext2 commands can be moved out of the menuentry sections to apply to all sections of the file. This leads to a simple section like: menuentry "Linux 2.6.35.4-lfs-6.7" { linux /boot/vmlinux-2.6.35.4-lfs-6.7 root=/dev/sda2 ro } • Passing a UUID to the kernel requires an initial ram disk (initrd) not built by LFS. • If the /boot partition is installed on a separate partition, the linux and initrd lines should not have the string /boot prefixed to the file names. • In this example the kernel files for a Ubuntu installation are also found in /boot.

8.4.3. Testing the Configuration
The core image of GRUB is also a Multiboot kernel, so if you already have GRUB Legacy loaded you can load GRUB-1.98 through your old boot loader. To accomplish this, you will need to exit the chroot environment and re-enter it to finish the few remaining portions of the book. /sbin/reboot ... grub> root (hd0,1) grub> kernel /boot/grub/core.img grub> boot Note that the GRUB commands above are assumed to be GRUB Legacy. At this point the GRUB prompt will appear (very similar to GRUB Legacy) and you can explore the interface or boot to one of the systems in the grub.cfg file.

8.4.4. Updating the Master Boot Record
If you tested the GRUB configuration as specified above, re-enter the chroot environment.

Warning
The following command will overwrite the current boot loader. Do not run the command if this is not desired, for example, if using a third party boot manager to manage the Master Boot Record (MBR). Update the MBR with: grub-setup '<DEVICE>' Change the DEVICE above to your boot disk, normally '(hd0)' or /dev/sda. If using (hd0) be sure to escape the parentheses with backslashes or single quotes to prevent the shell from interpreting them as a sub-shell. 221

Note
The root setting is the default value if a 'set root' instruction is not found in grub.cfg. This is the partition that is searched for the kernel and other supporting files. It is different from the 'root=' parameter on the 'linux' line in the configuration line. The latter is the partition the kernel mounts as '/'. In the example grub.cfg above, both values point to /dev/sda2, but if there is a separate boot partition, they will be different.

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Chapter 9. The End
9.1. The End
Well done! The new LFS system is installed! We wish you much success with your shiny new custom-built Linux system. It may be a good idea to create an /etc/lfs-release file. By having this file, it is very easy for you (and for us if you need to ask for help at some point) to find out which LFS version is installed on the system. Create this file by running: echo 6.7 > /etc/lfs-release

9.2. Get Counted
Now that you have finished the book, do you want to be counted as an LFS user? Head over to http://www. linuxfromscratch.org/cgi-bin/lfscounter.cgi and register as an LFS user by entering your name and the first LFS version you have used. Let's reboot into LFS now.

9.3. Rebooting the System
Now that all of the software has been installed, it is time to reboot your computer. However, you should be aware of a few things. The system you have created in this book is quite minimal, and most likely will not have the functionality you would need to be able to continue forward. By installing a few extra packages from the BLFS book while still in our current chroot environment, you can leave yourself in a much better position to continue on once you reboot into your new LFS installation. Installing a text mode web browser, such as Lynx, you can easily view the BLFS book in one virtual terminal, while building packages in another. The GPM package will also allow you to perform copy/paste actions in your virtual terminals. Lastly, if you are in a situation where static IP configuration does not meet your networking requirements, installing packages such as Dhcpcd or PPP at this point might also be useful. Now that we have said that, lets move on to booting our shiny new LFS installation for the first time! First exit from the chroot environment: logout Then unmount the virtual file systems: umount umount umount umount umount -v -v -v -v -v $LFS/dev/pts $LFS/dev/shm $LFS/dev $LFS/proc $LFS/sys

Unmount the LFS file system itself: umount -v $LFS 223

Linux From Scratch - Version 6.7 If multiple partitions were created, unmount the other partitions before unmounting the main one, like this: umount -v $LFS/usr umount -v $LFS/home umount -v $LFS Now, reboot the system with: shutdown -r now Assuming the GRUB boot loader was set up as outlined earlier, the menu is set to boot LFS 6.7 automatically. When the reboot is complete, the LFS system is ready for use and more software may be added to suit your needs.

9.4. What Now?
Thank you for reading this LFS book. We hope that you have found this book helpful and have learned more about the system creation process. Now that the LFS system is installed, you may be wondering “What next?” To answer that question, we have compiled a list of resources for you. • Maintenance Bugs and security notices are reported regularly for all software. Since an LFS system is compiled from source, it is up to you to keep abreast of such reports. There are several online resources that track such reports, some of which are shown below: • Freshmeat.net (http://freshmeat.net/) Freshmeat can notify you (via email) of new versions of packages installed on your system. • CERT (Computer Emergency Response Team) CERT has a mailing list that publishes security alerts concerning various operating systems and applications. Subscription information is available at http://www.us-cert.gov/cas/signup.html. • Bugtraq Bugtraq is a full-disclosure computer security mailing list. It publishes newly discovered security issues, and occasionally potential fixes for them. Subscription information is available at http://www.securityfocus.com/ archive. • Beyond Linux From Scratch The Beyond Linux From Scratch book covers installation procedures for a wide range of software beyond the scope of the LFS Book. The BLFS project is located at http://www.linuxfromscratch.org/blfs/. • LFS Hints The LFS Hints are a collection of educational documents submitted by volunteers in the LFS community. The hints are available at http://www.linuxfromscratch.org/hints/list.html. • Mailing lists There are several LFS mailing lists you may subscribe to if you are in need of help, want to stay current with the latest developments, want to contribute to the project, and more. See Chapter 1 - Mailing Lists for more information. 224

Linux From Scratch - Version 6.7 • The Linux Documentation Project The goal of The Linux Documentation Project (TLDP) is to collaborate on all of the issues of Linux documentation. The TLDP features a large collection of HOWTOs, guides, and man pages. It is located at http:// www.tldp.org/.

Appendix C. Dependencies
Every package built in LFS relies on one or more other packages in order to build and install properly. Some packages even participate in circular dependencies, that is, the first package depends on the second which in turn depends on the first. Because of these dependencies, the order in which packages are built in LFS is very important. The purpose of this page is to document the dependencies of each package built in LFS. For each package we build, we have listed three, and sometimes four, types of dependencies. The first lists what other packages need to be available in order to compile and install the package in question. The second lists what packages, in addition to those on the first list, need to be available in order to run the test suites. The third list of dependencies are packages that require this package to be built and installed in its final location before they are built and installed. In most cases, this is because these packages will hardcode paths to binaries within their scripts. If not built in a certain order, this could result in paths of /tools/bin/[binary] being placed inside scripts installed to the final system. This is obviously not desirable. The last list of dependencies are optional packages that are not addressed in LFS, but could be useful to the user. These packages may have additional mandatory or optional dependencies of their own. For these dependencies, the recommeded practice is to install them after completion of the LFS book and then go back an rebuild the LFS package. In several cases, reinstallation is addressed in BLFS.

Appendix D. Boot and sysconfig scripts version-20100627
The scripts in this appendix are listed by the directory where they normally reside. The order is /etc/rc.d/init.d, /etc/sysconfig, /etc/sysconfig/network-devices, and /etc/sysconfig/network-devices/services. Within each section, the files are listed in the order they are normally called.

## Set Cursor Position Commands, used SET_COL="\\033[${COL}G" # at the SET_WCOL="\\033[${WCOL}G" # at the CURS_UP="\\033[1A\\033[0G" # Up one

via $ECHO $COL char $WCOL char line, at the 0'th char

## Set color commands, used via $ECHO # Please consult `man console_codes for more information # under the "ECMA-48 Set Graphics Rendition" section # # Warning: when switching from a 8bit to a 9bit font, # the linux console will reinterpret the bold (1;) to # the top 256 glyphs of the 9bit font. This does # not affect framebuffer consoles NORMAL="\\033[0;39m" # Standard console grey SUCCESS="\\033[1;32m" # Success is green WARNING="\\033[1;33m" # Warnings are yellow FAILURE="\\033[1;31m" # Failures are red INFO="\\033[1;36m" # Information is light cyan BRACKET="\\033[1;34m" # Brackets are blue STRING_LENGTH="0" # the length of the current message

D.23. /etc/sysconfig/modules
######################################################################## # Begin /etc/sysconfig/modules # # Description : Module auto-loading configuration # # Authors : # # Version : 00.00 # # Notes : The syntax of this file is as follows: # <module> [<arg1> <arg2> ...] # # Each module should be on it's own line, and any options that you want # passed to the module should follow it. The line deliminator is either # a space or a tab. ######################################################################## # End /etc/sysconfig/modules

D.24. /etc/sysconfig/createfiles
######################################################################## # Begin /etc/sysconfig/createfiles # # Description : Createfiles script config file # # Authors : # # Version : 00.00 # # Notes : The syntax of this file is as follows: # if type is equal to "file" or "dir" # <filename> <type> <permissions> <user> <group> # if type is equal to "dev" # <filename> <type> <permissions> <user> <group> <devtype> <major> <minor> # # <filename> is the name of the file which is to be created # <type> is either file, dir, or dev. # file creates a new file # dir creates a new directory # dev creates a new device # <devtype> is either block, char or pipe # block creates a block device # char creates a character deivce # pipe creates a pipe, this will ignore the <major> and <minor> fields # <major> and <minor> are the major and minor numbers used for the device. ######################################################################## # End /etc/sysconfig/createfiles

D.25. /etc/sysconfig/network-devices/ifup
#!/bin/sh

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######################################################################## # Begin $network_devices/ifup # # Description : Interface Up # # Authors : Nathan Coulson - nathan@linuxfromscratch.org # Kevin P. Fleming - kpfleming@linuxfromscratch.org # # Version : 00.00 # # Notes : the IFCONFIG variable is passed to the scripts found # in the services directory, to indicate what file the # service should source to get environmental variables. # ######################################################################## . /etc/sysconfig/rc . ${rc_functions} # Collect a list of configuration files for our interface if [ -n "${2}" ]; then for file in ${@#$1} # All parameters except $1 do FILES="${FILES} ${network_devices}/ifconfig.${1}/${file}" done elif [ -d "${network_devices}/ifconfig.${1}" ]; then FILES=`echo ${network_devices}/ifconfig.${1}/*` else FILES="${network_devices}/ifconfig.${1}" fi boot_mesg "Bringing up the ${1} interface..." boot_mesg_flush # Process each configruation file for file in ${FILES}; do # skip backup files if [ "${file}" != "${file%""~""}" ]; then continue fi if [ ! -f "${file}" ]; then boot_mesg "${file} is not a network configuration file or directory." ${WARNING} echo_warning continue fi ( . ${file} # Will not process this service if started by boot, and ONBOOT # is not set to yes if [ "${IN_BOOT}" = "1" -a "${ONBOOT}" != "yes" ]; then continue fi # Will not process this service if started by hotplug, and # ONHOTPLUG is not set to yes

Linux From Scratch - Version 6.7
if [ -n "${2}" ]; then for file in ${@#$1}; do # All parameters except $1 FILES="${FILES} ${network_devices}/ifconfig.${1}/${file}" done elif [ -d "${network_devices}/ifconfig.${1}" ]; then FILES=`echo ${network_devices}/ifconfig.${1}/*` else FILES="${network_devices}/ifconfig.${1}" fi # Reverse the order configuration files are processed in for file in ${FILES}; do FILES2="${file} ${FILES2}" done FILES=${FILES2} # Process each configuration file for file in ${FILES}; do # skip backup files if [ "${file}" != "${file%""~""}" ]; then continue fi if [ ! -f "${file}" ]; then boot_mesg "${file} is not a network configuration file or directory." ${WARNING} echo_warning continue fi ( . ${file} # Will not process this service if started by boot, and ONBOOT # is not set to yes if [ "${IN_BOOT}" = "1" -a "${ONBOOT}" != "yes" ]; then continue fi # Will not process this service if started by hotplug, and # ONHOTPLUG is not set to yes if [ "${IN_HOTPLUG}" = "1" -a "${ONHOTPLUG}" != "yes" ]; then continue fi # This will run the service script, if SERVICE is set if [ -n "${SERVICE}" -a -x "${network_devices}/services/${SERVICE}" ]; then if ip link show ${1} > /dev/null 2>&1 then IFCONFIG=${file} ${network_devices}/services/${SERVICE} ${1} down else boot_mesg "Interface ${1} doesn't exist." ${WARNING} echo_warning fi else boot_mesg -n "Unable to process ${file}. Either" ${FAILURE} boot_mesg -n " the SERVICE variable was not set," boot_mesg " or the specified service cannot be executed." echo_failure

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